Command Behavior

Table of Contents
ar — create and maintain library archives
at — examine or delete jobs for later execution
awk — pattern scanning and processing language
batch — execute commands when the system load permits
bc — An arbitrary precision calculator language
cat — concatenate and print files
chfn — change user name and information
chgrp — change group ownership
chmod — change file access permissions
chown — change file access permissions
chsh — change login shell
col — filter reverse line feeds from input
cp — copy files and directories
cpio — copy file archives in and out
csplit — split a file into sections determined by context lines
crontab — maintain crontab files for individual users
cut — split a file into sections determined by context lines
date — print or set the system date and time
dd — convert and copy a file
df — report filesystem disk space usage
diff — find differences between two files
dmesg — print or control the kernel ring buffer
du — estimate file space usage
echo — display a line of text
egrep — search a file with an ERE pattern
env — run a program in a modified environment
expand — convert tabs to spaces
expr — evaluate expressions
fgrep — search a file with an ERE pattern
file — determine file type
find — search for files in a directory hierarchy
fuser — identify processes using files or sockets
gencat — generate a formatted message catalogue
grep — print lines matching a pattern
groupadd — Create a new group
groupdel — Delete a group
groupmod — Modify a group
groups — Display a group
gzip — compress or expand files
gunzip — uncompress files
head — output the first part of files
hostname — show the system's host name
iconv — show the system's host name
install — copy files and set attributes
ipcrm — Create a new user or update default new user information
ipcs — copy files and set attributes
killall — kill processes by name
ln — make links between files
localedef — split a file into sections determined by context lines
login — Begin session on the system
lpr — off line print
ls — list directory contents
lsb_release — print distribution specific information
m4 — macro processor
make — maintain, update and regenerate groups of programs
man — display system documentation
md5sum — generates or checks MD5 message digests
mkdir — make directories
mknod — make block or character special files
mktemp — make temporary file name (unique)
more — file perusal filter for crt viewing
mount — Create a new user or update default new user information
mv — move (rename) files
newgrp — Change group ID
nice — nice run a program with modified scheduling priority
nl — number lines of files
nohup — nohup run a command immune to hangups, with output to a non-tty
od — dump files in octal and other formats
passwd — change user password
paste — merge lines of files
patch — apply a diff file to an original
pathchk — check whether file names are valid or portable.
pidof — find the process ID of a running program.
pr — split a file into sections determined by context lines
printf — and print data.
pwd — print name of current/working directory.
renice — alter priority of running processes
rm — remove files or directories.
rmdir — remove empty directories.
rsync — faster, flexible replacement for rcp
sed — stream editor
sendmail — an electronic mail transport agent
shutdown — bring the system down
sleep — delay for a specified amount of time
sort — sort, merge or sequence check text files
split — split a file into pieces
strip — remove unnecessary information from executable files
su — Change user ID or become super-user
sum — print checksum and block count of a file
sync — flush filesystem buffers
tail — output the last part of files
tar — file archiver
tee — read from standard input and write to standard output and files
test — check file types and compare values
time — run programs and summarize system resource usage
touch — change file access and modification times
tr — translate or delete characters
tty — print the file name of the terminal connected to standard input
umount — unmount file systems
uname — return system name
unexpand — convert spaces to tabs
uniq — remove duplicate lines from a sorted file
useradd — Create a new user or update default new user information
userdel — Delete a user account and related files
usermod — Modify a user account
wc — print the number of bytes, words, and lines in files
xargs — build and execute command lines from standard input

This section contains descriptions of commands that are not documented by other standards, or descriptions of the difference from other standards.