Common commands

Command and keyword cheat sheet.

The following table describes common shell commands:

Command	Description
>	Redirects, creates, or overwrites a file.
»	Appends to a file.
&	Executes the program in the background.
*	Matches any number of characters.
?	Matches a single character.
awk	Programming language to parse characters.
basename file	Displays base filename of file
cal	Displays a calendar.
chgrp	Changes the file group.
chmod	Changes the file modes (permissions).
cut	Writes out selected characters.
diff file1 file2	Compares two files.
df	Displays filesystem statistics.
sdiff file1 file2	Compares two files, side-by-side.
date	Displays system data and time.
chown	Changes the file owner.
egrep	Pattern matching with extended regex.
file	Prints the file type.
find	Locates files and directories.
head	Views the top of the file.
iostat	Shows input/output status.
last	Shows login history since the `wtmp` file was created
more	Displays the contents of a file, one page at a time.
netstat	Shows network status.
passwd	Changes the user password.
ps	Displays information on currently running processes.
sar	Reports system activity.
sed	Programming language for character substitution.
sleep length	Pauses execution for length number of seconds.
spell file	Checks spelling on file.
tail	Views the end of the file.
tr chars1 chars2	Translates `chars1` into the format specified by `chars2`
wc	Counts number of words, lines, and characters in a file.
w	Extended `who` command that also provides `uptime` output. Displays information about who is on the system.
who	Displays information about who is on the system.
whoami	Displays `$LOGNAME` or `$USER` env vars.
who am i	Displays login name, terminal, login date/time, and where logged in.
vmstat	Shows virtual memory status.