simple spellcheck
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@ -150,7 +150,7 @@
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<primary>memory management</primary>
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<primary>memory management</primary>
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</indexterm>component manages the memory usage of the system: it keeps
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</indexterm>component manages the memory usage of the system: it keeps
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track of used and unused memory, assigns memory to processes who require
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track of used and unused memory, assigns memory to processes who require
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it and ensures that processes can't manipulate each other's data. To do
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it and ensures that processes can't manipulate the data of one another. To do
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this, it uses the concept of virtual memory addresses: addresses for one
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this, it uses the concept of virtual memory addresses: addresses for one
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process are not the real addresses, and the kernel keeps track of the
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process are not the real addresses, and the kernel keeps track of the
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correct mappings. It is also possible for data not to be really present
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correct mappings. It is also possible for data not to be really present
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@ -436,7 +436,7 @@
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installation options exist. You can install a distribution from a
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installation options exist. You can install a distribution from a
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network using net booting (a popular approach in enterprise
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network using net booting (a popular approach in enterprise
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environments as it makes unattended installations possible) or from
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environments as it makes unattended installations possible) or from
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within another operationg system.</para>
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within another operating system.</para>
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</listitem>
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</listitem>
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<listitem>
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<listitem>
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@ -473,9 +473,9 @@
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</listitem>
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</listitem>
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<listitem>
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<listitem>
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<para>Is internationalisation of the software important?</para>
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<para>Is internationalization of the software important?</para>
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<para>Some distributions are targetting specific user groups tied to
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<para>Some distributions are targeting specific user groups tied to
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their language and geography. There are distributions that are fully
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their language and geography. There are distributions that are fully
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localized to a specific group (say "Belgian Dutch-speaking users" or
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localized to a specific group (say "Belgian Dutch-speaking users" or
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"Canadian French-speaking users"), but also distributions that try to
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"Canadian French-speaking users"), but also distributions that try to
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@ -520,10 +520,10 @@
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<listitem>
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<listitem>
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<para>What policies does the distribution put on its software?</para>
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<para>What policies does the distribution put on its software?</para>
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<para>Organisations like FSF have a vision on how the (software) world
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<para>Organizations like FSF have a vision on how the (software) world
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should look like. Many distributions offer a way of implementing these
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should look like. Many distributions offer a way of implementing these
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visions. For instance, some distributions only allow software that is
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visions. For instance, some distributions only allow software that is
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licensed under a FSF-approved license. Other distributions allow users
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licensed under an FSF-approved license. Other distributions allow users
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to use non-free software. There are distributions that implement a
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to use non-free software. There are distributions that implement a
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higher security vision in the distribution, offering a more hardened
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higher security vision in the distribution, offering a more hardened
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approach to operating systems.</para>
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approach to operating systems.</para>
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@ -811,7 +811,7 @@
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as a vulnerability is found or reported. There is often no need for a
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as a vulnerability is found or reported. There is often no need for a
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desktop user to obtain commercial support as the freely available
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desktop user to obtain commercial support as the freely available
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support channels offer a major advantage compared to some other,
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support channels offer a major advantage compared to some other,
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propriatary operating systems.</para>
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proprietary operating systems.</para>
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</section>
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</section>
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<section>
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<section>
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@ -958,7 +958,7 @@
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<para>However, another trend is also emerging: more and more games are
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<para>However, another trend is also emerging: more and more games are
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only being released on consoles, dropping the PC environment
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only being released on consoles, dropping the PC environment
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alltogether. I personally don't know how games will evolve in the
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altogether. I personally don't know how games will evolve in the
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future, but I think that real action games will focus on game consoles
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future, but I think that real action games will focus on game consoles
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more.</para>
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more.</para>
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@ -249,7 +249,7 @@
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<para>Companies that <emphasis>sell</emphasis> software are of course
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<para>Companies that <emphasis>sell</emphasis> software are of course
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often against free software. When these companies major income depends
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often against free software. When these companies major income depends
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on the sales of their software, it would not be viable to make the
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on the sales of their software, it would not be viable to make the
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software free. If they would, competiting companies would have full
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software free. If they would, competing companies would have full
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access to the source code and improve their own product with it.</para>
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access to the source code and improve their own product with it.</para>
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<para>I don't think this is a disadvantage though. Software companies
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<para>I don't think this is a disadvantage though. Software companies
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contributing it to the software project itself.</para>
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contributing it to the software project itself.</para>
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<para>A major proof of this is the acceptance of free software by major
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<para>A major proof of this is the acceptance of free software by major
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software players such as Sun Microsystems and IBM, and the emergance of
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software players such as Sun Microsystems and IBM, and the emergence of
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new software players that build their business upon free software, such
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new software players that build their business upon free software, such
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as RedHat or MySQL<indexterm>
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as RedHat or MySQL<indexterm>
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<primary>MySQL</primary>
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<primary>MySQL</primary>
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distribution has to acquire itself (like infrastructure).</para>
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distribution has to acquire itself (like infrastructure).</para>
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<para>Most distributions have free downloads with online documentation
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<para>Most distributions have free downloads with online documentation
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and wonderfull community support (active mailing lists or Internet
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and wonderful community support (active mailing lists or Internet
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fora), which is why Linux is that popular: you can download, install and
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fora), which is why Linux is that popular: you can download, install and
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use several distributions to decide which one is best for you. You can
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use several distributions to decide which one is best for you. You can
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try the software (without loosing any functionality) and you don't even
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try the software (without loosing any functionality) and you don't even
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<para>Some distributions are only available when you pay for it. In that
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<para>Some distributions are only available when you pay for it. In that
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case you often pay for the support or for additional software in the
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case you often pay for the support or for additional software in the
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distribution which isn't freely available. A popular distribution is
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distribution which isn't freely available. A popular distribution is
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RedHat Enterprise Linux, a Linux distribution specifically targetting
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RedHat Enterprise Linux, a Linux distribution specifically targeting
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companies who want to set up Linux servers. You don't just pay for the
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companies who want to set up Linux servers. You don't just pay for the
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support, but also for the resources that RedHat has put in the
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support, but also for the resources that RedHat has put in the
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distribution to make it certified for other software (such as Oracle and
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distribution to make it certified for other software (such as Oracle and
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<listitem>
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<listitem>
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<para><emphasis>development releases</emphasis> are intermediate
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<para><emphasis>development releases</emphasis> are intermediate
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releases, similar to nightly snapshots, but somewhat more
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releases, similar to nightly snapshots, but somewhat more
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coördinated by the developers. They usually have a
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coordinated by the developers. They usually have a
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ChangeLog<indexterm>
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ChangeLog<indexterm>
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<primary>ChangeLog</primary>
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<primary>ChangeLog</primary>
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</indexterm> which lists the changes in it since the previous
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</indexterm> which lists the changes in it since the previous
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<para>If at any time all the copyright owners of the free software
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<para>If at any time all the copyright owners of the free software
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decide that the software falls under a different license which you don't
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decide that the software falls under a different license which you don't
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agree after, you can take the sourcecode of the moment right before the
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agree after, you can take the source code of the moment right before the
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copyright holders decided to switch the licenses and continue the
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copyright holders decided to switch the licenses and continue the
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development under that license (as that software is still under the
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development under that license (as that software is still under the
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original license and not the new one). This process (where a group of
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original license and not the new one). This process (where a group of
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effort to ensure that no fragmentation occurs in the Linux world.</para>
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effort to ensure that no fragmentation occurs in the Linux world.</para>
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<para>Because the LSB is a broad standard, it comprises of other
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<para>Because the LSB is a broad standard, it comprises of other
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standards, including the forementioned FHS but also the <emphasis>Single
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standards, including the aforementioned FHS but also the <emphasis>Single
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Unix Specification</emphasis><indexterm>
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Unix Specification</emphasis><indexterm>
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<primary>Single Unix Specification</primary>
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<primary>Single Unix Specification</primary>
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</indexterm> (SUS<indexterm>
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</indexterm> (SUS<indexterm>
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<listitem>
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<listitem>
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<para>How is it possible that many distributions allow you to upgrade
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<para>How is it possible that many distributions allow you to upgrade
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to the latest version without needing an installation CD or
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to the latest version without needing an installation CD or
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reinstallation from scratch?</para>
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re-installation from scratch?</para>
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</listitem>
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</listitem>
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</orderedlist>
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</orderedlist>
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</section>
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</section>
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the Internet as main communication channel. Hence, these communities
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the Internet as main communication channel. Hence, these communities
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aren't clustered in space like real life communities would, but are
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aren't clustered in space like real life communities would, but are
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scattered throughout the world. Nevertheless, the Internet ensures that
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scattered throughout the world. Nevertheless, the Internet ensures that
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participants of a community, even when they are lightyears (figure of
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participants of a community, even when they are light years (figure of
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speech) apart, talk to each other the same way as neighbours do.</para>
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speech) apart, talk to each other the same way as neighbors do.</para>
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<para>The Internet is a great asset for these communities: you are not
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<para>The Internet is a great asset for these communities: you are not
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judged based on the color of your skin, your age or your looks. What
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judged based on the color of your skin, your age or your looks. What
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how you react in discussions. Debates in a community can often become
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how you react in discussions. Debates in a community can often become
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quite vivid, especially when the subject is one where facts aren't
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quite vivid, especially when the subject is one where facts aren't
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sufficient to provide good answers. And when these discussions change from
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sufficient to provide good answers. And when these discussions change from
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debates into almost insulting fights, a flamewar<indexterm>
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debates into almost insulting fights, a flame war<indexterm>
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<primary>flamewar</primary>
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<primary>flame war</primary>
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</indexterm> is born.</para>
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</indexterm> is born.</para>
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<para>In flamewars, facts and reason are often far away. You should
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<para>In flame wars, facts and reason are often far away. You should
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definitely try to avoid flamewars for discussions where decisions have to
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definitely try to avoid flame wars for discussions where decisions have to
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be made, but it is impossible to really prevent them as they are the
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be made, but it is impossible to really prevent them as they are the
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result of people who have an active interest in a subject they are eager
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result of people who have an active interest in a subject they are eager
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to defend, especially when there is no clear answer to the question that
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to defend, especially when there is no clear answer to the question that
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started the flamewar.</para>
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started the flame war.</para>
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<para>Examples of such flamewars are ``What is the best Linux
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<para>Examples of such flame wars are ``What is the best Linux
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distribution?'' or ``What text editor should I choose?'' because these
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distribution?'' or ``What text editor should I choose?'' because these
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questions don't have clear answers: the best distribution for one person
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questions don't have clear answers: the best distribution for one person
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might be the worst for another, and there are many text editors around. In
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might be the worst for another, and there are many text editors around. In
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shouldn't argue about tastes and colors) and this is very true for these
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shouldn't argue about tastes and colors) and this is very true for these
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kind of questions.</para>
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kind of questions.</para>
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<para>When you don't have a choice, flamewars don't exist: you cannot
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<para>When you don't have a choice, flame wars don't exist: you cannot
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compare one product with itself. But in the free software world, choice is
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compare one product with itself. But in the free software world, choice is
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an important concept. You have the choice between many free operating
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an important concept. You have the choice between many free operating
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systems (next to Linux you have many BSD flavors, Sun Solaris 10 and even
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systems (next to Linux you have many BSD flavors, Sun Solaris 10 and even
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quite large. The Gentoo community for instance is known for its
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quite large. The Gentoo community for instance is known for its
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responsiveness: the Gentoo chat channel is always alive (with more than
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responsiveness: the Gentoo chat channel is always alive (with more than
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800 participants at any time) as is its forum (with more than a thousand
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800 participants at any time) as is its forum (with more than a thousand
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posts per day) and mailinglists. Of course, general flamewars on
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posts per day) and mailinglists. Of course, general flame wars on
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distributions are often on more neutral grounds, but heated discussions on
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distributions are often on more neutral grounds, but heated discussions on
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other topics are a daily routine.</para>
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other topics are a daily routine.</para>
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<para>For this reason, most communities have people who keep the
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<para>For this reason, most communities have people who keep the
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discussions sane and prevent flamewars from growing too much. People who
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discussions sane and prevent flame wars from growing too much. People who
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try to induce flamewars on the communication channels (called
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try to induce flame wars on the communication channels (called
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<emphasis>trolls</emphasis><indexterm>
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<emphasis>trolls</emphasis><indexterm>
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<primary>troll</primary>
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<primary>troll</primary>
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</indexterm>) are taken care of by these operators: channel operators
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</indexterm>) are taken care of by these operators: channel operators
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<title>Local Communities</title>
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<title>Local Communities</title>
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<para>A specific type of community is one which is local in space. Such
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<para>A specific type of community is one which is local in space. Such
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communities often organise meetings (conferences, talks, barbequeues,
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communities often organize meetings (conferences, talks, barbequeues,
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...) and offer help to people local to the location where the community
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...) and offer help to people local to the location where the community
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is hosted.</para>
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is hosted.</para>
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<primary>LUG</primary>
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<primary>LUG</primary>
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</indexterm>s (Linux User Group<indexterm>
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</indexterm>s (Linux User Group<indexterm>
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<primary>Linux User Group</primary>
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<primary>Linux User Group</primary>
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</indexterm>s) are succesful examples of such communities: these
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</indexterm>s) are successful examples of such communities: these
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groups aggregate together, debating on the evolution in the Linux world
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groups aggregate together, debating on the evolution in the Linux world
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and help others with Linux installations (Linux Install Fests<indexterm>
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and help others with Linux installations (Linux Install Fests<indexterm>
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<primary>Linux Install Fest</primary>
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<primary>Linux Install Fest</primary>
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<para>When people want to discuss a particular software topic or
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<para>When people want to discuss a particular software topic or
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distribution, online communities are often formed. These communities do
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distribution, online communities are often formed. These communities do
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not (or to a less extend) organise meetings at a specific location
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not (or to a less extend) organize meetings at a specific location
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(often called "in real life") but rather use the Internet as the meeting
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(often called "in real life") but rather use the Internet as the meeting
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place ("online" meetings).</para>
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place ("online" meetings).</para>
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</listitem>
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</listitem>
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<listitem>
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<listitem>
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<para>documentation, more specialised to the software title but
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<para>documentation, more specialized to the software title but
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often also localised (translated)</para>
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often also localised (translated)</para>
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</listitem>
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</listitem>
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</itemizedlist>
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</itemizedlist>
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<listitem>
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<listitem>
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<para>Mailinglists, which is similar (function-wise) to web forums,
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<para>Mailinglists, which is similar (function-wise) to web forums,
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but then organised through e-mail. People subscribe to a mailinglist
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but then organized through e-mail. People subscribe to a mailinglist
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and then receive all mails sent to that mailinglist to their
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and then receive all mails sent to that mailinglist to their
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personal mailbox. Replies to these mails are sent back to the
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personal mailbox. Replies to these mails are sent back to the
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mailinglists where they are again distributed to all mailinglist
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mailinglists where they are again distributed to all mailinglist
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</itemizedlist>
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</itemizedlist>
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|
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<para>The restriction deletion flag needs some explanation. It is used
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<para>The restriction deletion flag needs some explanation. It is used
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on world-writeable directories (a well-known example is
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on world-writable directories (a well-known example is
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<filename>/tmp</filename>, where temporary files can be stored) and used
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<filename>/tmp</filename>, where temporary files can be stored) and used
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to prevent users to remove files they didn't create. A world-writable
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to prevent users to remove files they didn't create. A world-writable
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directory would otherwise allow other users to remove files from that
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directory would otherwise allow other users to remove files from that
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directory. The <filename>~</filename> can be used in two ways:
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directory. The <filename>~</filename> can be used in two ways:
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either to denote your home directory (<command>cd
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either to denote your home directory (<command>cd
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~/Documents</command> goes to
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~/Documents</command> goes to
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<filename>/home/captain/Documents</filename>) or someone elses home
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<filename>/home/captain/Documents</filename>) or someone else's home
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directory. In the latter case, you append the user name to the
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directory. In the latter case, you append the user name to the
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<filename>~</filename> sign, so: "<command>cd
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<filename>~</filename> sign, so: "<command>cd
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~raghat/public_html/</command>" translates to
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~raghat/public_html/</command>" translates to
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@ -596,7 +596,7 @@ Documents Movies Music Pictures
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same.</para>
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same.</para>
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<section>
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<section>
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<title>Analysing ls -l output</title>
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<title>Analyzing ls -l output</title>
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|
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<para>You will find that you often use "<command>ls -l</command>" to
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<para>You will find that you often use "<command>ls -l</command>" to
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get the necessary information about a file or directory. As such I
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get the necessary information about a file or directory. As such I
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|
|
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successor, <emphasis>reiser4</emphasis><indexterm>
|
successor, <emphasis>reiser4</emphasis><indexterm>
|
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<primary>reiser4</primary>
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<primary>reiser4</primary>
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</indexterm>, is still quite premature and is, due to the
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</indexterm>, is still quite premature and is, due to the
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inprisonment of the main developer Hans Reiser, not being
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imprisonment of the main developer Hans Reiser, not being
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developed that actively anymore.</para>
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developed that actively anymore.</para>
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</listitem>
|
</listitem>
|
||||||
</itemizedlist>
|
</itemizedlist>
|
||||||
|
@ -678,7 +678,7 @@ Filename Type Size Used Priority
|
||||||
|
|
||||||
<listitem>
|
<listitem>
|
||||||
<para><filename>/usr/lib</filename> contains all the libraries for
|
<para><filename>/usr/lib</filename> contains all the libraries for
|
||||||
the abovementioned programs</para>
|
the above mentioned programs</para>
|
||||||
</listitem>
|
</listitem>
|
||||||
|
|
||||||
<listitem>
|
<listitem>
|
||||||
|
@ -782,7 +782,7 @@ Filename Type Size Used Priority
|
||||||
file system. It is the first file system that is mounted when the kernel
|
file system. It is the first file system that is mounted when the kernel
|
||||||
boots, and your system will not function properly if the kernel detects
|
boots, and your system will not function properly if the kernel detects
|
||||||
corruption on this file system. Also, due to the nature of the boot
|
corruption on this file system. Also, due to the nature of the boot
|
||||||
process, this file system will eventually become writeable (as the boot
|
process, this file system will eventually become writable (as the boot
|
||||||
process needs to store its state information, etc.)</para>
|
process needs to store its state information, etc.)</para>
|
||||||
|
|
||||||
<para>Some locations on the root file system need to remain on the root
|
<para>Some locations on the root file system need to remain on the root
|
||||||
|
@ -886,7 +886,7 @@ Filename Type Size Used Priority
|
||||||
|
|
||||||
<para>Another advantage of using a separate file system for /home is
|
<para>Another advantage of using a separate file system for /home is
|
||||||
when you would decide to switch distributions: you can reuse your /home
|
when you would decide to switch distributions: you can reuse your /home
|
||||||
file system for other Linux distributions (or after a reinstallation of
|
file system for other Linux distributions (or after a re-installation of
|
||||||
your Linux distribution).</para>
|
your Linux distribution).</para>
|
||||||
</section>
|
</section>
|
||||||
</section>
|
</section>
|
||||||
|
@ -929,7 +929,7 @@ Filename Type Size Used Priority
|
||||||
|
|
||||||
<para>However, supporting these flags wouldn't make a system secure: you
|
<para>However, supporting these flags wouldn't make a system secure: you
|
||||||
want to mix these privileges based on who works with the file. For
|
want to mix these privileges based on who works with the file. For
|
||||||
instance, the system configuration files should only be writeable by the
|
instance, the system configuration files should only be writable by the
|
||||||
administrator(s); some might not even be readable by the users (like the
|
administrator(s); some might not even be readable by the users (like the
|
||||||
file containing the user passwords).</para>
|
file containing the user passwords).</para>
|
||||||
|
|
||||||
|
@ -980,7 +980,7 @@ Filename Type Size Used Priority
|
||||||
<programlisting>$ <command>ls -l /etc/fstab</command>
|
<programlisting>$ <command>ls -l /etc/fstab</command>
|
||||||
-rw-r--r-- 1 root root 905 Nov 21 09:10 /etc/fstab</programlisting>
|
-rw-r--r-- 1 root root 905 Nov 21 09:10 /etc/fstab</programlisting>
|
||||||
|
|
||||||
<para>In the above example, the fstab file is writeable by the root user
|
<para>In the above example, the fstab file is writable by the root user
|
||||||
(rw-) and readable by anyone else (r--).</para>
|
(rw-) and readable by anyone else (r--).</para>
|
||||||
|
|
||||||
<para>In case of a directory,</para>
|
<para>In case of a directory,</para>
|
||||||
|
@ -1011,7 +1011,7 @@ Filename Type Size Used Priority
|
||||||
drwxr-x--- 2 root root 4096 Nov 26 18:17 /etc/cron.daily/</programlisting>
|
drwxr-x--- 2 root root 4096 Nov 26 18:17 /etc/cron.daily/</programlisting>
|
||||||
|
|
||||||
<para>In the above example, the cron.daily directory is viewable (r),
|
<para>In the above example, the cron.daily directory is viewable (r),
|
||||||
writeable (w) and "enterable" (x) by the root user. People in the root
|
writable (w) and "enterable" (x) by the root user. People in the root
|
||||||
group have view- and enter rights (r-x) whereas all other people have no
|
group have view- and enter rights (r-x) whereas all other people have no
|
||||||
rights to view, write or enter the directory (---).</para>
|
rights to view, write or enter the directory (---).</para>
|
||||||
|
|
||||||
|
@ -1249,7 +1249,7 @@ Change: 2010-02-06 13:50:43.000000000 +0100</programlisting>
|
||||||
</itemizedlist>
|
</itemizedlist>
|
||||||
|
|
||||||
<para>Then you can set (=), add (+) or remove (-) privileges. For
|
<para>Then you can set (=), add (+) or remove (-) privileges. For
|
||||||
instance, to make <filename>/etc/passwd</filename> writeable for the
|
instance, to make <filename>/etc/passwd</filename> writable for the
|
||||||
members of the owning group:</para>
|
members of the owning group:</para>
|
||||||
|
|
||||||
<programlisting># <command>chmod g+w /etc/passwd</command></programlisting>
|
<programlisting># <command>chmod g+w /etc/passwd</command></programlisting>
|
||||||
|
|
|
@ -11,7 +11,7 @@
|
||||||
<title>Parent and Child Relationships</title>
|
<title>Parent and Child Relationships</title>
|
||||||
|
|
||||||
<para>Each Linux (and Unix) process has a parent (except for the top
|
<para>Each Linux (and Unix) process has a parent (except for the top
|
||||||
process) and can have one or more childs. The relationship is crafted
|
process) and can have one or more children. The relationship is crafted
|
||||||
when a process is launched: the process that launched the new process
|
when a process is launched: the process that launched the new process
|
||||||
becomes the parent of that process. As a user, you might not know what
|
becomes the parent of that process. As a user, you might not know what
|
||||||
process you are currently working in. Every program is a process, being
|
process you are currently working in. Every program is a process, being
|
||||||
|
@ -85,7 +85,7 @@ init-+-acpid
|
||||||
process launches a shell process with the user id and group id of the
|
process launches a shell process with the user id and group id of the
|
||||||
user that logged on, so every command the user launches takes the user
|
user that logged on, so every command the user launches takes the user
|
||||||
id and group id of that user, since the parent process of every launched
|
id and group id of that user, since the parent process of every launched
|
||||||
command is either the beforementioned shell process or one of its child
|
command is either the before mentioned shell process or one of its child
|
||||||
processes.</para>
|
processes.</para>
|
||||||
|
|
||||||
<para>Some processes however explicitly ask the Linux kernel to use a
|
<para>Some processes however explicitly ask the Linux kernel to use a
|
||||||
|
@ -110,7 +110,7 @@ init-+-acpid
|
||||||
has root privileges rather than the privileges for the user. For the
|
has root privileges rather than the privileges for the user. For the
|
||||||
<command>passwd</command> command, this is necessary because it needs to
|
<command>passwd</command> command, this is necessary because it needs to
|
||||||
update the password files (<filename>/etc/passwd</filename> and
|
update the password files (<filename>/etc/passwd</filename> and
|
||||||
<filename>/etc/shadow</filename>) which are only writeable by the root
|
<filename>/etc/shadow</filename>) which are only writable by the root
|
||||||
user (the <filename>/etc/shadow</filename> file is not even readable for
|
user (the <filename>/etc/shadow</filename> file is not even readable for
|
||||||
regular users).</para>
|
regular users).</para>
|
||||||
</section>
|
</section>
|
||||||
|
@ -142,7 +142,7 @@ init-+-acpid
|
||||||
</listitem>
|
</listitem>
|
||||||
|
|
||||||
<listitem>
|
<listitem>
|
||||||
<para>TTY - controlling terminal (this is Unix inheritage where
|
<para>TTY - controlling terminal (this is Unix heritage where
|
||||||
users were logged on through terminals, pts is a
|
users were logged on through terminals, pts is a
|
||||||
pseudoterminal)</para>
|
pseudoterminal)</para>
|
||||||
</listitem>
|
</listitem>
|
||||||
|
@ -213,7 +213,7 @@ Swap: 2008084k total, 132k used, 2007952k free, 776060k cached
|
||||||
user launches 3 xterms inside a graphical session he will be shown as
|
user launches 3 xterms inside a graphical session he will be shown as
|
||||||
four logged on users) and the load average.</para>
|
four logged on users) and the load average.</para>
|
||||||
|
|
||||||
<para>The load average is something many people misinterprete. The
|
<para>The load average is something many people misinterpret. The
|
||||||
load average shows the number of processes that were running or asking
|
load average shows the number of processes that were running or asking
|
||||||
for CPU time during the given interval. In the above example, this
|
for CPU time during the given interval. In the above example, this
|
||||||
means that:</para>
|
means that:</para>
|
||||||
|
@ -396,7 +396,7 @@ apache2 4346 root 3u IPv4 11484 TCP *:https (LISTEN)</programlisti
|
||||||
process is still running, but it is running in the background. Most
|
process is still running, but it is running in the background. Most
|
||||||
daemons do not have the possibility to reattach to the session. Wether
|
daemons do not have the possibility to reattach to the session. Wether
|
||||||
or not a process is a daemon depends on the process itself as this is a
|
or not a process is a daemon depends on the process itself as this is a
|
||||||
pure programmatical decision.</para>
|
pure programmatic decision.</para>
|
||||||
|
|
||||||
<para>Backgrounded processes however are processes that stay in the
|
<para>Backgrounded processes however are processes that stay in the
|
||||||
running session, but do not "lock" the input devices (keyboard). As a
|
running session, but do not "lock" the input devices (keyboard). As a
|
||||||
|
@ -427,7 +427,7 @@ apache2 4346 root 3u IPv4 11484 TCP *:https (LISTEN)</programlisti
|
||||||
|
|
||||||
<para>If you want to put a process that you are running in the
|
<para>If you want to put a process that you are running in the
|
||||||
background, use Ctrl-Z to put the process in the background. Ctrl-Z also
|
background, use Ctrl-Z to put the process in the background. Ctrl-Z also
|
||||||
pauzes the process, so if you want to continue the process in the
|
pauses the process, so if you want to continue the process in the
|
||||||
background, enter "<command>bg</command>" afterwards as well:</para>
|
background, enter "<command>bg</command>" afterwards as well:</para>
|
||||||
|
|
||||||
<programlisting># <command>eix-update</command>
|
<programlisting># <command>eix-update</command>
|
||||||
|
@ -496,7 +496,7 @@ apache2 4346 root 3u IPv4 11484 TCP *:https (LISTEN)</programlisti
|
||||||
even "wrap" return codes to this range. If a program would ever have a
|
even "wrap" return codes to this range. If a program would ever have a
|
||||||
return code of 512 for instance, it might be mapped into 0.</para>
|
return code of 512 for instance, it might be mapped into 0.</para>
|
||||||
|
|
||||||
<para>Every program that has succesfully finished its job will (or
|
<para>Every program that has successfully finished its job will (or
|
||||||
should) return code 0. A non-zero return code means that the application
|
should) return code 0. A non-zero return code means that the application
|
||||||
has failed to finish its tasks (completely).</para>
|
has failed to finish its tasks (completely).</para>
|
||||||
|
|
||||||
|
@ -516,7 +516,7 @@ $ <command>echo $?</command>
|
||||||
2</programlisting>
|
2</programlisting>
|
||||||
|
|
||||||
<para>These return codes are important as they are the means to
|
<para>These return codes are important as they are the means to
|
||||||
investigate if all commands went succesfully or not, allowing you to
|
investigate if all commands went successfully or not, allowing you to
|
||||||
write quite intelligent shell scripts which trigger several commands and
|
write quite intelligent shell scripts which trigger several commands and
|
||||||
include logic to handle command failures.</para>
|
include logic to handle command failures.</para>
|
||||||
</section>
|
</section>
|
||||||
|
@ -528,7 +528,7 @@ $ <command>echo $?</command>
|
||||||
Linux kernel does that for you, based on information about the process
|
Linux kernel does that for you, based on information about the process
|
||||||
itself, including but not limited to if the process is I/O-bound (as
|
itself, including but not limited to if the process is I/O-bound (as
|
||||||
such programs are most of the time user-interactive), its previous CPU
|
such programs are most of the time user-interactive), its previous CPU
|
||||||
consumation, possible locks it is holding and more.</para>
|
consumption, possible locks it is holding and more.</para>
|
||||||
|
|
||||||
<para>You can, however, inform the kernel on what you think the process'
|
<para>You can, however, inform the kernel on what you think the process'
|
||||||
priority ought to be. For this, you can set a
|
priority ought to be. For this, you can set a
|
||||||
|
@ -596,7 +596,7 @@ $ <command>echo $?</command>
|
||||||
|
|
||||||
<para>Its name might already inform you about its usual task: killing
|
<para>Its name might already inform you about its usual task: killing
|
||||||
processes. By default, if you want to terminate a process but you can't
|
processes. By default, if you want to terminate a process but you can't
|
||||||
commicate with the process directly (like hitting "Quit" or "Exit"), you
|
communicate with the process directly (like hitting "Quit" or "Exit"), you
|
||||||
should send a signal 15 (SIGTERM<indexterm>
|
should send a signal 15 (SIGTERM<indexterm>
|
||||||
<primary>SIGTERM</primary>
|
<primary>SIGTERM</primary>
|
||||||
</indexterm>) to the program. This is also what
|
</indexterm>) to the program. This is also what
|
||||||
|
|
Reference in New Issue