path: root/chapter06/coreutils.xml

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  <!ENTITY % general-entities SYSTEM "../general.ent">
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<sect1 id="ch-system-coreutils" xreflabel="Coreutils" role="wrap">
<title>Coreutils-&coreutils-version;</title>
<?dbhtml filename="coreutils.html"?>

<indexterm zone="ch-system-coreutils"><primary sortas="a-Coreutils">Coreutils</primary></indexterm>

<sect2 role="package"><title/>
<para>The Coreutils package contains utilities for showing and setting the
basic system characteristics.</para>

<segmentedlist>
<segtitle>&buildtime;</segtitle>
<segtitle>&diskspace;</segtitle>
<seglistitem><seg>0.9 SBU</seg><seg>69 MB</seg></seglistitem>
</segmentedlist>

<segmentedlist>
<segtitle>Coreutils installation depends on</segtitle>
<seglistitem><seg>Bash, Binutils, Coreutils, Diffutils, GCC,
Gettext, Glibc, Grep, Make, Perl, Sed</seg></seglistitem>
</segmentedlist>
</sect2>

<sect2 role="installation">
<title>Installation of Coreutils</title>

<para>Normally the functionality of <command>uname</command> is somewhat
broken, in that the <parameter>-p</parameter> switch always returns
<computeroutput>unknown</computeroutput>.  The following patch fixes this behavior for Intel
architectures:</para>

<screen><userinput>patch -Np1 -i ../coreutils-&coreutils-version;-uname-2.patch</userinput></screen>

<para>Prevent Coreutils from installing binaries that will be later be installed
by other programs:</para>

<screen><userinput>patch -Np1 -i ../coreutils-&coreutils-version;-suppress_hostname_uptime_kill_su-1.patch</userinput></screen>

<para>Now prepare Coreutils for compilation:</para>

<screen><userinput>DEFAULT_POSIX2_VERSION=199209 ./configure --prefix=/usr</userinput></screen>

<para>Compile the package:</para>

<screen><userinput>make</userinput></screen>

<para>The test suite of Coreutils makes several assumptions about the presence
of files and users that aren't valid this early in the LFS build. We will
therefore have to set up a few things before being able to run the tests. If
you choose not to run these tests, skip down to <quote>Install the
package</quote>.</para>

<para>Create two dummy groups and a dummy user name:</para>

<screen><userinput>echo "dummy1:x:1000" &gt;&gt; /etc/group
echo "dummy2:x:1001:dummy" &gt;&gt; /etc/group
echo "dummy:x:1000:1000:::/bin/bash" &gt;&gt; /etc/passwd</userinput></screen>

<para>Now you're all set to run the test suite. First run the few tests that
are meant to be run as <emphasis>root</emphasis>:</para>

<screen><userinput>make NON_ROOT_USERNAME=dummy check-root</userinput></screen>

<para>Then run the remainder of the tests as the <emphasis>dummy</emphasis>
user:</para>

<screen><userinput>src/su dummy -c "make RUN_EXPENSIVE_TESTS=yes check"</userinput></screen>

<para>When you're done testing, remove the dummy user and groups:</para>

<screen><userinput>sed -i '/dummy/d' /etc/passwd /etc/group</userinput></screen>

<para>Install the package:</para>

<screen><userinput>make install</userinput></screen>

<para>And move some programs to their proper locations:</para>

<screen><userinput>mv /usr/bin/{[,basename,cat,chgrp,chmod,chown,cp,dd,df} /bin
mv /usr/bin/{date,echo,false,head,install,ln,ls} /bin
mv /usr/bin/{mkdir,mknod,mv,pwd,rm,rmdir,sync} /bin
mv /usr/bin/{sleep,stty,test,touch,true,uname} /bin
mv /usr/bin/chroot /usr/sbin</userinput></screen>

<para>Finally, create a symlink to be FHS-compliant:</para>

<screen><userinput>ln -s ../../bin/install /usr/bin</userinput></screen>

</sect2>


<sect2 id="contents-coreutils" role="content"><title>Contents of Coreutils</title>

<segmentedlist>
<segtitle>Installed programs</segtitle>
<seglistitem><seg>basename, cat, chgrp, chmod,
chown, chroot, cksum, comm, cp, csplit, cut, date, dd, df, dir, dircolors,
dirname, du, echo, env, expand, expr, factor, false, fmt, fold, groups, head,
hostid, hostname, id, install, join, link, ln, logname, ls, md5sum,
mkdir, mkfifo, mknod, mv, nice, nl, nohup, od, paste, pathchk, pinky, pr,
printenv, printf, ptx, pwd, readlink, rm, rmdir, seq, sha1sum, shred, sleep,
sort, split, stat, stty, su, sum, sync, tac, tail, tee, test, touch, tr, true,
tsort, tty, uname, unexpand, uniq, unlink, uptime, users, vdir, wc, who,
whoami and yes</seg></seglistitem>
</segmentedlist>

<variablelist><title>Short descriptions</title>

<varlistentry id="basename">
<term><command>basename</command></term>
<listitem>
<indexterm zone="ch-system-coreutils basename"><primary sortas="b-basename">basename</primary></indexterm>
<para>strips any path and a given suffix from the given file name.</para>
</listitem>
</varlistentry>

<varlistentry id="cat">
<term><command>cat</command></term>
<listitem>
<indexterm zone="ch-system-coreutils cat"><primary sortas="b-cat">cat</primary></indexterm>
<para>concatenates files to standard output.</para>
</listitem>
</varlistentry>

<varlistentry id="chgrp">
<term><command>chgrp</command></term>
<listitem>
<indexterm zone="ch-system-coreutils chgrp"><primary sortas="b-chgrp">chgrp</primary></indexterm>
<para>changes the group ownership of each given file to the given group. The 
group can be either given a a name or a numeric ID.</para>
</listitem>
</varlistentry>

<varlistentry id="chmod">
<term><command>chmod</command></term>
<listitem>
<indexterm zone="ch-system-coreutils chmod"><primary sortas="b-chmod">chmod</primary></indexterm>
<para>changes the permissions of each given file
to the given mode. The mode can be either a symbolic representation of the
changes to make, or an octal number representing the new permissions.</para>
</listitem>
</varlistentry>

<varlistentry id="chown">
<term><command>chown</command></term>
<listitem>
<indexterm zone="ch-system-coreutils chown"><primary sortas="b-chown">chown</primary></indexterm>
<para>changes the user and/or group ownership of
each given file to the given user:group pair.</para>
</listitem>
</varlistentry>

<varlistentry id="chroot">
<term><command>chroot</command></term>
<listitem>
<indexterm zone="ch-system-coreutils chroot"><primary sortas="b-chroot">chroot</primary></indexterm>
<para>runs a given command with the specified directory as the 
<filename class="directory">/</filename> directory. The given command can be an interactive shell.
On most systems only <emphasis>root</emphasis> can do this.</para>
</listitem>
</varlistentry>

<varlistentry id="cksum">
<term><command>cksum</command></term>
<listitem>
<indexterm zone="ch-system-coreutils cksum"><primary sortas="b-cksum">cksum</primary></indexterm>
<para>prints the CRC (Cyclic Redundancy Check) checksum and the byte
counts of each specified file.</para>
</listitem>
</varlistentry>

<varlistentry id="comm">
<term><command>comm</command></term>
<listitem>
<indexterm zone="ch-system-coreutils comm"><primary sortas="b-comm">comm</primary></indexterm>
<para>compares two sorted files, outputting in
three columns the lines that are unique, and the lines that are common.</para>
</listitem>
</varlistentry>

<varlistentry id="cp">
<term><command>cp</command></term>
<listitem>
<indexterm zone="ch-system-coreutils cp"><primary sortas="b-cp">cp</primary></indexterm>
<para>copies files.</para>
</listitem>
</varlistentry>

<varlistentry id="csplit">
<term><command>csplit</command></term>
<listitem>
<indexterm zone="ch-system-coreutils csplit"><primary sortas="b-csplit">csplit</primary></indexterm>
<para>splits a given file into several new files,
separating them according to given patterns or line numbers, and outputting
the byte count of each new file.</para>
</listitem>
</varlistentry>

<varlistentry id="cut">
<term><command>cut</command></term>
<listitem>
<indexterm zone="ch-system-coreutils cut"><primary sortas="b-cut">cut</primary></indexterm>
<para>prints parts of lines, selecting the parts
according to given fields or positions.</para>
</listitem>
</varlistentry>

<varlistentry id="date">
<term><command>date</command></term>
<listitem>
<indexterm zone="ch-system-coreutils date"><primary sortas="b-date">date</primary></indexterm>
<para>displays the current time in the given format, or sets the system date.</para>
</listitem>
</varlistentry>

<varlistentry id="dd">
<term><command>dd</command> </term>
<listitem>
<indexterm zone="ch-system-coreutils dd"><primary sortas="b-dd">dd</primary></indexterm>
<para>copies a file using the given block size and
count, while optionally performing conversions on it.</para>
</listitem>
</varlistentry>

<varlistentry id="df">
<term><command>df</command></term>
<listitem>
<indexterm zone="ch-system-coreutils df"><primary sortas="b-df">df</primary></indexterm>
<para>reports the amount of disk space available
(and used) on all mounted file systems, or only on the file systems holding the
given files.</para>
</listitem>
</varlistentry>

<varlistentry id="dir">
<term><command>dir</command></term>
<listitem>
<indexterm zone="ch-system-coreutils dir"><primary sortas="b-dir">dir</primary></indexterm>
<para>is the same as <command>ls</command>.</para>
</listitem>
</varlistentry>

<varlistentry id="dircolors">
<term><command>dircolors</command></term>
<listitem>
<indexterm zone="ch-system-coreutils dircolors"><primary sortas="b-dircolors">dircolors</primary></indexterm>
<para>outputs commands to set the LS_COLOR
environment variable, to change the color scheme used by <command>ls</command>.</para>
</listitem>
</varlistentry>

<varlistentry id="dirname">
<term><command>dirname</command></term>
<listitem>
<indexterm zone="ch-system-coreutils dirname"><primary sortas="b-dirname">dirname</primary></indexterm>
<para>strips the non-directory suffix from a given file name.</para>
</listitem>
</varlistentry>

<varlistentry id="du">
<term><command>du</command></term>
<listitem>
<indexterm zone="ch-system-coreutils du"><primary sortas="b-du">du</primary></indexterm>
<para>reports the amount of disk space used by the
current directory, or by each of the given directories including all their
subdirectories, or by each of the given files.</para>
</listitem>
</varlistentry>

<varlistentry id="echo">
<term><command>echo</command></term>
<listitem>
<indexterm zone="ch-system-coreutils echo"><primary sortas="b-echo">echo</primary></indexterm>
<para>displays the given strings.</para>
</listitem>
</varlistentry>

<varlistentry id="env">
<term><command>env</command></term>
<listitem>
<indexterm zone="ch-system-coreutils env"><primary sortas="b-env">env</primary></indexterm>
<para>runs a command in a modified environment.</para>
</listitem>
</varlistentry>

<varlistentry id="expand">
<term><command>expand</command></term>
<listitem>
<indexterm zone="ch-system-coreutils expand"><primary sortas="b-expand">expand</primary></indexterm>
<para>converts tabs to spaces.</para>
</listitem>
</varlistentry>

<varlistentry id="expr">
<term><command>expr</command></term>
<listitem>
<indexterm zone="ch-system-coreutils expr"><primary sortas="b-expr">expr</primary></indexterm>
<para>evaluates expressions.</para>
</listitem>
</varlistentry>

<varlistentry id="factor">
<term><command>factor</command></term>
<listitem>
<indexterm zone="ch-system-coreutils factor"><primary sortas="b-factor">factor</primary></indexterm>
<para>prints the prime factors of all specified integer numbers.</para>
</listitem>
</varlistentry>

<varlistentry id="false">
<term><command>false</command></term>
<listitem>
<indexterm zone="ch-system-coreutils false"><primary sortas="b-false">false</primary></indexterm>
<para>does nothing, unsuccessfully. It always
exits with a status code indicating failure.</para>
</listitem>
</varlistentry>

<varlistentry id="mt">
<term><command>fmt</command></term>
<listitem>
<indexterm zone="ch-system-coreutils mt"><primary sortas="b-mt">mt</primary></indexterm>
<para>reformats the paragraphs in the given files.</para>
</listitem>
</varlistentry>

<varlistentry id="fold">
<term><command>fold</command></term>
<listitem>
<indexterm zone="ch-system-coreutils fold"><primary sortas="b-fold">fold</primary></indexterm>
<para>wraps the lines in the given files.</para>
</listitem>
</varlistentry>

<varlistentry id="groups-coreutils">
<term><command>groups</command></term>
<listitem>
<indexterm zone="ch-system-coreutils groups-coreutils"><primary sortas="b-groups-coreutils">groups</primary></indexterm>
<para>reports a user's group memberships.</para>
</listitem>
</varlistentry>

<varlistentry id="head">
<term><command>head</command></term>
<listitem>
<indexterm zone="ch-system-coreutils head"><primary sortas="b-head">head</primary></indexterm>
<para>prints the first ten lines (or the given number of lines) of each given file.</para>
</listitem>
</varlistentry>

<varlistentry id="hostid">
<term><command>hostid</command></term>
<listitem>
<indexterm zone="ch-system-coreutils hostid"><primary sortas="b-hostid">hostid</primary></indexterm>
<para>reports the numeric identifier (in hexadecimal) of the host.</para>
</listitem>
</varlistentry>

<varlistentry id="hostname-coreutils">
<term><command>hostname</command></term>
<listitem>
<indexterm zone="ch-system-coreutils hostname-coreutils"><primary sortas="b-hostname-coreutils">hostname</primary></indexterm>
<para>reports or sets the name of the host.</para>
</listitem>
</varlistentry>

<varlistentry id="id">
<term><command>id</command></term>
<listitem>
<indexterm zone="ch-system-coreutils id"><primary sortas="b-id">id</primary></indexterm>
<para>reports the effective user ID, group ID, and
group memberships of the current user, or of a given user.</para>
</listitem>
</varlistentry>

<varlistentry id="install">
<term><command>install</command> </term>
<listitem>
<indexterm zone="ch-system-coreutils install"><primary sortas="b-install">install</primary></indexterm>
<para>copies files while setting their
permission modes and, if possible, their owner and group.</para>
</listitem>
</varlistentry>

<varlistentry id="join">
<term><command>join</command></term>
<listitem>
<indexterm zone="ch-system-coreutils join"><primary sortas="b-join">join</primary></indexterm>
<para>joins from two files the lines that have identical join fields.</para>
</listitem>
</varlistentry>

<varlistentry id="link">
<term><command>link</command></term>
<listitem>
<indexterm zone="ch-system-coreutils link"><primary sortas="b-link">link</primary></indexterm>
<para>creates a hard link with the given name to the given file.</para>
</listitem>
</varlistentry>

<varlistentry id="ln">
<term><command>ln</command></term>
<listitem>
<indexterm zone="ch-system-coreutils ln"><primary sortas="b-ln">ln</primary></indexterm>
<para>makes hard links or soft links between files.</para>
</listitem>
</varlistentry>

<varlistentry id="logname">
<term><command>logname</command></term>
<listitem>
<indexterm zone="ch-system-coreutils logname"><primary sortas="b-logname">logname</primary></indexterm>
<para>reports the current user's login name.</para>
</listitem>
</varlistentry>

<varlistentry id="ls">
<term><command>ls</command></term>
<listitem>
<indexterm zone="ch-system-coreutils ls"><primary sortas="b-ls">ls</primary></indexterm>
<para>lists the contents of each given directory.
By default it orders the files and subdirectories alphabetically.</para>
</listitem>
</varlistentry>

<varlistentry id="md5sum">
<term><command>md5sum</command></term>
<listitem>
<indexterm zone="ch-system-coreutils md5sum"><primary sortas="b-md5sum">md5sum</primary></indexterm>
<para>reports or checks MD5 (Message Digest 5) checksums.</para>
</listitem>
</varlistentry>

<varlistentry id="mkdir">
<term><command>mkdir</command></term>
<listitem>
<indexterm zone="ch-system-coreutils mkdir"><primary sortas="b-mkdir">mkdir</primary></indexterm>
<para>creates directories with the given names.</para>
</listitem>
</varlistentry>

<varlistentry id="mkfifo">
<term><command>mkfifo</command></term>
<listitem>
<indexterm zone="ch-system-coreutils mkfifo"><primary sortas="b-mkfifo">mkfifo</primary></indexterm>
<para>creates FIFOs (First-In, First-Out, a <quote>named pipe</quote> in UNIX parlance) with
the given names.</para>
</listitem>
</varlistentry>

<varlistentry id="mknod">
<term><command>mknod</command></term>
<listitem>
<indexterm zone="ch-system-coreutils mknod"><primary sortas="b-mknod">mknod</primary></indexterm>
<para>creates device nodes with the given names.
A device node is a character special file, or a block special file, or a FIFO.</para>
</listitem>
</varlistentry>

<varlistentry id="mv">
<term><command>mv</command></term>
<listitem>
<indexterm zone="ch-system-coreutils mv"><primary sortas="b-mv">mv</primary></indexterm>
<para>moves or renames files or directories.</para>
</listitem>
</varlistentry>

<varlistentry id="nice">
<term><command>nice</command></term>
<listitem>
<indexterm zone="ch-system-coreutils nice"><primary sortas="b-nice">nice</primary></indexterm>
<para>runs a program with modified scheduling priority.</para>
</listitem>
</varlistentry>

<varlistentry id="nl">
<term><command>nl</command></term>
<listitem>
<indexterm zone="ch-system-coreutils nl"><primary sortas="b-nl">nl</primary></indexterm>
<para>numbers the lines from the given files.</para>
</listitem>
</varlistentry>

<varlistentry id="nohup">
<term><command>nohup</command></term>
<listitem>
<indexterm zone="ch-system-coreutils nohup"><primary sortas="b-nohup">nohup</primary></indexterm>
<para>runs a command immune to hangups, with
output redirected to a log file.</para>
</listitem>
</varlistentry>

<varlistentry id="od">
<term><command>od</command></term>
<listitem>
<indexterm zone="ch-system-coreutils od"><primary sortas="b-od">od</primary></indexterm>
<para>dumps files in octal and other formats.</para>
</listitem>
</varlistentry>

<varlistentry id="paste">
<term><command>paste</command></term>
<listitem>
<indexterm zone="ch-system-coreutils paste"><primary sortas="b-paste">paste</primary></indexterm>
<para>merges the given files, joining
sequentially corresponding lines side by side, separated by tab characters..</para>
</listitem>
</varlistentry>

<varlistentry id="pathchk">
<term><command>pathchk</command></term>
<listitem>
<indexterm zone="ch-system-coreutils pathchk"><primary sortas="b-pathchk">pathchk</primary></indexterm>
<para>checks whether file names are valid or portable.</para>
</listitem>
</varlistentry>

<varlistentry id="pinky">
<term><command>pinky</command></term>
<listitem>
<indexterm zone="ch-system-coreutils pinky"><primary sortas="b-pinky">pinky</primary></indexterm>
<para>is a lightweight finger. It reports some information about the given users.</para>
</listitem>
</varlistentry>

<varlistentry id="pr">
<term><command>pr</command></term>
<listitem>
<indexterm zone="ch-system-coreutils pr"><primary sortas="b-pr">pr</primary></indexterm>
<para>paginates and columnates files for printing.</para>
</listitem>
</varlistentry>

<varlistentry id="printenv">
<term><command>printenv</command></term>
<listitem>
<indexterm zone="ch-system-coreutils printenv"><primary sortas="b-printenv">printenv</primary></indexterm>
<para>prints the environment.</para>
</listitem>
</varlistentry>

<varlistentry id="printf">
<term><command>printf</command></term>
<listitem>
<indexterm zone="ch-system-coreutils printf"><primary sortas="b-printf">printf</primary></indexterm>
<para>prints the given arguments according to the
given format -- much like the C printf function.</para>
</listitem>
</varlistentry>

<varlistentry id="ptx">
<term><command>ptx</command></term>
<listitem>
<indexterm zone="ch-system-coreutils ptx"><primary sortas="b-ptx">ptx</primary></indexterm>
<para>produces from the contents of the given files
a permuted index, with each keyword in its context.</para>
</listitem>
</varlistentry>

<varlistentry id="pwd">
<term><command>pwd</command></term>
<listitem>
<indexterm zone="ch-system-coreutils pwd"><primary sortas="b-pwd">pwd</primary></indexterm>
<para>reports the name of the current directory.</para>
</listitem>
</varlistentry>

<varlistentry id="readlink">
<term><command>readlink</command></term>
<listitem>
<indexterm zone="ch-system-coreutils readlink"><primary sortas="b-readlink">readlink</primary></indexterm>
<para>reports the value of the given symbolic link.</para>
</listitem>
</varlistentry>

<varlistentry id="rm">
<term><command>rm</command></term>
<listitem>
<indexterm zone="ch-system-coreutils rm"><primary sortas="b-rm">rm</primary></indexterm>
<para>removes files or directories.</para>
</listitem>
</varlistentry>

<varlistentry id="rmdir">
<term><command>rmdir</command></term>
<listitem>
<indexterm zone="ch-system-coreutils rmdir"><primary sortas="b-rmdir">rmdir</primary></indexterm>
<para>removes directories, if they are empty.</para>
</listitem>
</varlistentry>

<varlistentry id="seq">
<term><command>seq</command></term>
<listitem>
<indexterm zone="ch-system-coreutils seq"><primary sortas="b-seq">seq</primary></indexterm>
<para>prints a sequence of numbers, within a given
range and with a given increment.</para>
</listitem>
</varlistentry>

<varlistentry id="sha1sum">
<term><command>sha1sum</command></term>
<listitem>
<indexterm zone="ch-system-coreutils sha1sum"><primary sortas="b-sha1sum">sha1sum</primary></indexterm>
<para>prints or checks 160-bit SHA1 checksums.</para>
</listitem>
</varlistentry>

<varlistentry id="shred">
<term><command>shred</command></term>
<listitem>
<indexterm zone="ch-system-coreutils shred"><primary sortas="b-shred">shred</primary></indexterm>
<para>overwrites the given files repeatedly with
strange patterns, to make it real hard to recover the data.</para>
</listitem>
</varlistentry>

<varlistentry id="sleep">
<term><command>sleep</command></term>
<listitem>
<indexterm zone="ch-system-coreutils sleep"><primary sortas="b-sleep">sleep</primary></indexterm>
<para>pauses for the given amount of time.</para>
</listitem>
</varlistentry>

<varlistentry id="sort">
<term><command>sort</command></term>
<listitem>
<indexterm zone="ch-system-coreutils sort"><primary sortas="b-sort">sort</primary></indexterm>
<para>sorts the lines from the given files.</para>
</listitem>
</varlistentry>

<varlistentry id="split">
<term><command>split</command></term>
<listitem>
<indexterm zone="ch-system-coreutils split"><primary sortas="b-split">split</primary></indexterm>
<para>splits the given file into pieces, by size or by numbspliter of lines.</para>
</listitem>
</varlistentry>

<varlistentry id="stty">
<term><command>stty</command></term>
<listitem>
<indexterm zone="ch-system-coreutils stty"><primary sortas="b-stty">stty</primary></indexterm>
<para>sets or reports terminal line settings.</para>
</listitem>
</varlistentry>

<varlistentry id="su">
<term><command>su</command></term>
<listitem>
<indexterm zone="ch-system-coreutils su"><primary sortas="b-su">su</primary></indexterm>
<para>runs a shell with substitute user and group IDs.</para>
</listitem>
</varlistentry>

<varlistentry id="sum">
<term><command>sum</command></term>
<listitem>
<indexterm zone="ch-system-coreutils sum"><primary sortas="b-sum">sum</primary></indexterm>
<para>prints checksum and block counts for each given file.</para>
</listitem>
</varlistentry>

<varlistentry id="sync">
<term><command>sync</command></term>
<listitem>
<indexterm zone="ch-system-coreutils sync"><primary sortas="b-sync">sync</primary></indexterm>
<para>flushes file system buffers. It forces
changed blocks to disk and updates the super block.</para>
</listitem>
</varlistentry>

<varlistentry id="tac">
<term><command>tac</command></term>
<listitem>
<indexterm zone="ch-system-coreutils tac"><primary sortas="b-tac">tac</primary></indexterm>
<para>concatenates the given files in reverse.</para>
</listitem>
</varlistentry>

<varlistentry id="tail">
<term><command>tail</command></term>
<listitem>
<indexterm zone="ch-system-coreutils tail"><primary sortas="b-tail">tail</primary></indexterm>
<para>prints the last ten lines (or the given number of lines) of each given file.</para>
</listitem>
</varlistentry>

<varlistentry id="tee">
<term><command>tee</command></term>
<listitem>
<indexterm zone="ch-system-coreutils tee"><primary sortas="b-tee">tee</primary></indexterm>
<para>reads from standard input while writing both
to standard output and to the given files.</para>
</listitem>
</varlistentry>

<varlistentry id="test">
<term><command>test</command></term>
<listitem>
<indexterm zone="ch-system-coreutils test"><primary sortas="b-test">test</primary></indexterm>
<para>compares values and checks file types.</para>
</listitem>
</varlistentry>

<varlistentry id="touch">
<term><command>touch</command></term>
<listitem>
<indexterm zone="ch-system-coreutils touch"><primary sortas="b-touch">touch</primary></indexterm>
<para>changes file timestamps, setting the access
and modification times of the given files to the current time. Files that do
not exist are created with zero length.</para>
</listitem>
</varlistentry>

<varlistentry id="tr">
<term><command>tr</command></term>
<listitem>
<indexterm zone="ch-system-coreutils tr"><primary sortas="b-tr">tr</primary></indexterm>
<para>translates, squeezes, and deletes the given
characters from standard input.</para>
</listitem>
</varlistentry>

<varlistentry id="true">
<term><command>true</command></term>
<listitem>
<indexterm zone="ch-system-coreutils true"><primary sortas="b-true">true</primary></indexterm>
<para>does nothing, successfully. It always exits
with a status code indicating success.</para>
</listitem>
</varlistentry>

<varlistentry id="tsort">
<term><command>tsort</command></term>
<listitem>
<indexterm zone="ch-system-coreutils tsort"><primary sortas="b-tsort">tsort</primary></indexterm>
<para>performs a topological sort. It writes a
totally ordered list according to the partial ordering in a given file.</para>
</listitem>
</varlistentry>

<varlistentry id="tty">
<term><command>tty</command></term>
<listitem>
<indexterm zone="ch-system-coreutils tty"><primary sortas="b-tty">tty</primary></indexterm>
<para>reports the file name of the terminal connected to standard input.</para>
</listitem>
</varlistentry>

<varlistentry id="uname">
<term><command>uname</command></term>
<listitem>
<indexterm zone="ch-system-coreutils uname"><primary sortas="b-uname">uname</primary></indexterm>
<para>reports system information.</para>
</listitem>
</varlistentry>

<varlistentry id="unexpand">
<term><command>unexpand</command></term>
<listitem>
<indexterm zone="ch-system-coreutils unexpand"><primary sortas="b-unexpand">unexpand</primary></indexterm>
<para>converts spaces to tabs.</para>
</listitem>
</varlistentry>

<varlistentry id="uniq">
<term><command>uniq</command></term>
<listitem>
<indexterm zone="ch-system-coreutils uniq"><primary sortas="b-uniq">uniq</primary></indexterm>
<para>discards all but one of successive identical lines.</para>
</listitem>
</varlistentry>

<varlistentry id="unlink">
<term><command>unlink</command></term>
<listitem>
<indexterm zone="ch-system-coreutils unlink"><primary sortas="b-unlink">unlink</primary></indexterm>
<para>removes the given file.</para>
</listitem>
</varlistentry>

<varlistentry id="uptime-coreutils">
<term><command>uptime</command></term>
<listitem>
<indexterm zone="ch-system-coreutils uptime-coreutils"><primary sortas="b-uptime-coreutils">uptime</primary></indexterm>
<para>reports how long the system has been
running, how many users are logged on, and the system load averages.</para>
</listitem>
</varlistentry>

<varlistentry id="users">
<term><command>users</command></term>
<listitem>
<indexterm zone="ch-system-coreutils users"><primary sortas="b-users">users</primary></indexterm>
<para>reports the names of the users currently logged on.</para>
</listitem>
</varlistentry>

<varlistentry id="vdir">
<term><command>vdir</command></term>
<listitem>
<indexterm zone="ch-system-coreutils vdir"><primary sortas="b-vdir">vdir</primary></indexterm>
<para>is the same as <command>ls -l</command>.</para>
</listitem>
</varlistentry>

<varlistentry id="wc">
<term><command>wc</command></term>
<listitem>
<indexterm zone="ch-system-coreutils wc"><primary sortas="b-wc">wc</primary></indexterm>
<para>reports the number of lines, words, and bytes
for each given file, and a total line when more than one file is given.</para>
</listitem>
</varlistentry>

<varlistentry id="who">
<term><command>who</command></term>
<listitem>
<indexterm zone="ch-system-coreutils who"><primary sortas="b-who">who</primary></indexterm>
<para>reports who is logged on.</para>
</listitem>
</varlistentry>

<varlistentry id="whoami">
<term><command>whoami</command></term>
<listitem>
<indexterm zone="ch-system-coreutils whoami"><primary sortas="b-whoami">whoami</primary></indexterm>
<para>reports the user name associated with the current effective user ID.</para>
</listitem>
</varlistentry>

<varlistentry id="yes">
<term><command>yes</command></term>
<listitem>
<indexterm zone="ch-system-coreutils yes"><primary sortas="b-yes">yes</primary></indexterm>
<para>outputs <quote>y</quote> or a given string repeatedly, until killed.</para>
</listitem>
</varlistentry>
</variablelist>

</sect2>

</sect1>