lfs-book-zh_CN/appendixa/coreutils-desc.xml

<sect2><title>Short descriptions</title>

<para><command>basename</command> strips any path and a given suffix from
the given file name.</para>

<para><command>cat</command> concatenates files to standard output.</para>

<para><command>chgrp</command> 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>

<para><command>chmod</command> 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>

<para><command>chown</command> changes the user and/or group ownership of
each given file to the given user:group pair.</para>

<para><command>chroot</command> runs a given command with the specified
directory as the <filename>/</filename> directory. The given command can be an
interactive shell. On most systems only <emphasis>root</emphasis> can do
this.</para>

<para><command>cksum</command> prints the CRC checksum and the byte
counts of each specified file.</para>

<para><command>comm</command> compares two sorted files, outputting in
three columns the lines that are unique, and the lines that are common.</para>

<para><command>cp</command> copies files.</para>

<para><command>csplit</command> 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>

<para><command>cut</command> prints parts of lines, selecting the parts
according to given fields or positions.</para>

<para><command>date</command> displays the current time in the given
format, or sets the system date.</para>

<para><command>dd</command> copies a file using the given blocksize and
count, while optionally performing conversions on it.</para>

<para><command>df</command> reports the amount of disk space available
(and used) on all mounted filesystems, or only on the filesystems holding the
given files.</para>

<para><command>dir</command> is the same as ls.</para>

<para><command>dircolors</command> outputs commands to set the LS_COLOR
environment variable, to change the color scheme used by ls.</para>

<para><command>dirname</command> strips the non-directory suffix from
a given file name.</para>

<para><command>du</command> 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>

<para><command>echo</command> displays the given strings.</para>

<para><command>env</command> runs a command in a modified environment.</para>

<para><command>expand</command> converts tabs to spaces.</para>

<para><command>expr</command> evaluates expressions.</para>

<para><command>factor</command> prints the prime factors of all specified
integer numbers.</para>

<para><command>false</command> does nothing, unsuccessfully. It always
exits with a status code indicating failure.</para>

<para><command>fmt</command> reformats the paragraphs in the given files.</para>

<para><command>fold</command> wraps the lines in the given files.</para>

<para><command>groups</command> reports a user's group memberships.</para>

<para><command>head</command> prints the first ten lines (or the given
number of lines) of each given file.</para>

<para><command>hostid</command> reports the numeric identifier
(in hexadecimal) of the host.</para>

<para><command>hostname</command> reports or sets the name of the
host.</para>

<para><command>id</command> reports the effective user ID, group ID, and
group memberships of the current user, or of a given user.</para>

<para><command>install</command> copies files while setting their
permission modes and, if possible, their owner and group.</para>

<para><command>join</command> joins from two files the lines that have
identical join fields.</para>

<para><command>link</command> creates a hard link with the given name
to the given file.</para>

<para><command>ln</command> makes hard links or soft links between files.</para>

<para><command>logname</command> reports the current user's login name.</para>

<para><command>ls</command> lists the contents of each given directory.
By default it orders the files and subdirectories alphabetically.</para>

<para><command>md5sum</command> reports or checks MD5 checksums.</para>

<para><command>mkdir</command> creates directories with the given names.</para>

<para><command>mkfifo</command> creates FIFOs with the given names.</para>

<para><command>mknod</command> creates device nodes with the given names.
A device node is a character special file, or a block special file, or a FIFO.</para>

<para><command>mv</command> moves or renames files or directories.</para>

<para><command>nice</command> runs a program with modified scheduling priority.</para>

<para><command>nl</command> numbers the lines from the given files.</para>

<para><command>nohup</command> runs a command immune to hangups, with
output redirected to a log file.</para>

<para><command>od</command> dumps files in octal and other formats.</para>

<para><command>paste</command> merges the given files, joining
sequentially corresponding lines side by side, separated by TABs.</para>

<para><command>pathchk</command> checks whether file names are valid
or portable.</para>

<para><command>pinky</command> is a lightweight finger. It reports
some information about the given users.</para>

<para><command>pr</command> paginates and columnates files for printing.</para>

<para><command>printenv</command> prints the environment.</para>

<para><command>printf</command> prints the given arguments according to the
given format -- much like the C printf function.</para>

<para><command>ptx</command> produces from the contents of the given files
a permuted index, with each keyword in its context.</para>

<para><command>pwd</command> reports the name of the current directory.</para>

<para><command>readlink</command> reports the value of the given symbolic
link.</para>

<para><command>rm</command> removes files or directories.</para>

<para><command>rmdir</command> removes directories, if they are empty.</para>

<para><command>seq</command> prints a sequence of numbers, within a given
range and with a given increment.</para>

<para><command>sha1sum</command> prints or checks 160-bit SHA1
checksums.</para>

<para><command>shred</command> overwrites the given files repeatedly with
strange patterns, to make it real hard to recover the data.</para>

<para><command>sleep</command> pauses for the given amount of time.</para>

<para><command>sort</command> sorts the lines from the given files.</para>

<para><command>split</command> splits the given file into pieces, by size
or by number of lines.</para>

<para><command>stty</command> sets or reports terminal line settings.</para>

<para><command>su</command> runs a shell with substitute user and group IDs.</para>

<para><command>sum</command> prints checksum and block counts for each
given file.</para>

<para><command>sync</command> flushes filesystem buffers. It forces
changed blocks to disk and updates the super block.</para>

<para><command>tac</command> concatenates the given files in reverse.</para>

<para><command>tail</command> prints the last ten lines (or the given
number of lines) of each given file.</para>

<para><command>tee</command> reads from standard input while writing both
to standard output and to the given files.</para>

<para><command>test</command> compares values and checks file types.</para>

<para><command>touch</command> 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>

<para><command>tr</command> translates, squeezes, and deletes the given
characters from standard input.</para>

<para><command>true</command> does nothing, successfully. It always exits
with a status code indicating success.</para>

<para><command>tsort</command> performs a topological sort. It writes a
totally ordered list according to the partial ordering in a given file.</para>

<para><command>tty</command> reports the file name of the terminal
connected to standard input.</para>

<para><command>uname</command> reports system information.</para>

<para><command>unexpand</command> converts spaces to tabs.</para>

<para><command>uniq</command> discards all but one of successive
identical lines.</para>

<para><command>unlink</command> removes the given file.</para>

<para><command>uptime</command> reports how long the system has been
running, how many users are logged on, and the system load averages.</para>

<para><command>users</command> reports the names of the users currently
logged on.</para>

<para><command>vdir</command> is the same as ls -l.</para>

<para><command>wc</command> reports the number of lines, words, and bytes
for each given file, and a total line when more than one file is given.</para>

<para><command>who</command> reports who is logged on.</para>

<para><command>whoami</command> reports the user name associated with the
current effective user ID.</para>

<para><command>yes</command> outputs 'y' or a given string repeatedly,
until killed.</para>

</sect2>