A
alias: Create an alias
awk: Find and Replace text within file(s) B
basename: Return just the file name alone
bzip2/bunzip2: Compress or decompress named file(s) C
cat: Display the contents of a file
cat -n: simple way to add line-numbers to the output of a command
cd: Change Directory
chgrp: Change group ownership
chmod: Change access permissions
chown: Change file owner and group
chroot: Run a command with a different root directory
clear: Clear terminal screen
cmp: Compare two files
comm: Compare two sorted files line by line
cp Copy one or more files to another location
crontab: Schedule a command to run at a later time D
date: Display or change the date & time
dc: Desk Calculator
dd: Data Dump - Convert and copy a file
df: Display free disk space
diff: Display the differences between two files
dir: Briefly list directory contents
dircolors: Colour setup for ls
dirname: Convert a full pathname to just a path
dmesg: Output is from the kernel booting, showing the devices it has found and if it has been able to configure them at all (aside from userland configuration).
du: Estimate file space usage E
echo: Display message on screen
egrep: Print lines matching a pattern (same as grep -E)
eject: Eject CD-ROM
env: Display, set, or remove environment variables
exit: Exit the shell (or press Ctrl-D)
export: Set an environment variable F
fdisk: Partition table manipulator for Linux
fgrep: Print lines matching a pattern (same as grep -F)
file: Tells what kind of files are those listed on command line
find: Search for files that meet a desired criteria
for: Expand words, and execute commands
format: Format disks or tapes
free: Display memory usage
fsck: Filesystem consistency check and repair.
ftp: Transfer/receive files from/to a remote host G
grep: Print lines matching a pattern
groups: Print group names a user is in
gzip/gunzip: Compress or decompress named file(s) H
head: Output the first part of file(s)
history: Command History
hostname: Print or set system name I
id: Print user and group id's
if/then/else/elif/fi Conditionally perform a command
info: Help info J
join: Joins lines on a common field K
kill: Stops a process from running
killall: Stops matching process from running L
less: Display output one screen at a time
ln: Make links between files
locate: Find files using an indexed list.
logname: Print current login name
logout: Exit a login shell
lpc: Line printer control program
lpr: Off line print
lprint: Print a file
lprintq: List the print queue
ls: List information about file(s) M
man: Help manual
mkdir: Create new folder(s)
more: Display output one screen at a time
mount: Mount a file system
mv: Move or rename files or directories N
nice: Set the priority of a command or job P
passwd: Modify a user password
printf: Format and print data
ps: Process Status. Lists running process
pwd: Print Working Directory Q
R
rgrep: Recursive grep
rm: Remove file(s)
rmdir: Remove folder(s)
rsync: Remote file copy (Synchronize file trees) using its own protocol. It may be used over an ssh or rsh connection. S
scp: Copy files between two machines over an ssh connection
sdiff: Merge two files interactively
sed: Stream Editor
select: Accept keyboard input
sftp: Secure file transfer (FTP over SSH)
shutdown: Shutdown or restart Linux
sleep: Delay for a specified time
sort: Sort text files
ssh: Secure Shell
su: Substitute user identity
sudo: Execute a command as another user
sync: Synchronize data on disk with memory T
tail: Output the last part of files
tar: Tape Archiver
time: Measure Program Resource Use
touch: Change file timestamps or create an empty file
top: List processes running on the system
traceroute: Trace Route to Host
tr: Translate, squeeze, and/or delete characters
true: Do nothing, successfully U
umask: Users file creation mask
umount: Unmount a device
uname: Print system information
uniq: Uniquify files
until: Execute commands (until error)
useradd: Create new user account
usermod: Modify user account
users: List users currently logged in V
vdir: Verbosely list directory contents (ls -l -b) W
watch: Execute/display a program periodically
wc: Print byte, word and line counts
which: Locate a program file in the user's path.
who: Print all usernames currently logged in
whoami: Print the current user id and name (`id -un') X
xargs: Execute utility, passing constructed argument list(s) Y
Z
other
. : See source
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