Linux Commands – A | |
| |
Command | Description |
accept | Accept or Reject jobs to a destination, such as a printer. |
access | Check a user’s RWX permission for a file. |
aclocal | GNU autoconf too |
aconnect | ALSA sequencer connection manager. |
acpi | Show information about the Advanced Configuration and Power Interface. |
acpi_available | Check if ACPI functionality exists on the system. |
acpid | Informs user-space programs about ACPI events. |
addr2line | Used to convert addresses into file names and line numbers. |
addresses | Formats for internet mail addresses. |
agetty | An alternative Linux Getty |
alias | Create an alias for Linux commands |
alsactl | Access advanced controls for ALSA soundcard driver. |
amidi | Perform read/write operation for ALSA RawMIDI ports. |
amixer | Access CLI-based mixer for ALSA soundcard driver. |
anacron | Used to run commands periodically. |
aplay | Sound recorder and player for CLI. |
aplaymidi | CLI utility used to play MIDI files. |
apm | Show Advanced Power Management (APM) hardware info on older systems. |
apmd | Used to handle events reported by APM BIOS drivers. |
apropos | Shows the list of all man pages containing a specific keyword |
apt | Advanced Package Tool, a package management system for Debian and derivatives. |
apt-get | Command-line utility to install/remove/update packages based on APT system. |
aptitude | Another utility to add/remove/upgrade packages based on the APT system. |
ar | A utility to create/modify/extract from archives. |
arch | Display print machine hardware name. |
arecord | Just like aplay, it’s a sound recorder and player for ALSA soundcard driver. |
arecordmidi | Record standard MIDI files. |
arp | Used to make changes to the system’s ARP cache |
as | A portable GNU assembler. |
aspell | An interactive spell checker utility. |
at | Used to schedule command execution at specified date & time, reading commands from an input file. |
atd | Used to execute jobs queued by the at command. |
atq | List a user’s pending jobs for the at command. |
atrm | Delete jobs queued by the at command. |
audiosend | Used to send an audio recording as an email. |
aumix | An audio mixer utility. |
autoconf | Generate configuration scripts from a TEMPLATE-FILE and send the output to standard output. |
autoheader | Create a template header for configure. |
automake | Creates GNU standards-compliant Makefiles from template files |
autoreconf | Update generated configuration files. |
autoscan | Generate a preliminary configure.in |
autoupdate | Update a configure.in file to newer autoconf. |
awk | Used to find and replace text in a file(s). |
| |
Linux Commands – B | |
| |
Command | Description |
badblocks | Search a disk partition for bad sectors. |
banner | Used to print characters as a poster. |
basename | Used to display filenames with directoy or suffix. |
bash | GNU Bourne-Again Shell. |
batch | Used to run commands entered on a standard input. |
bc | Access the GNU bc calculator utility. |
bg | Send processes to the background. |
biff | Notify about incoming mail and sender’s name on a system running comsat server. |
bind | Used to attach a name to a socket. |
bison | A GNU parser generator, compatible with yacc. |
break | Used to exit from a loop (eg: for, while, select). |
builtin | Used to run shell builtin commands, make custom functions for commands extending their functionality. |
bzcmp | Used to call the cmp program for bzip2 compressed files. |
bzdiff | Used to call the diff program for bzip2 compressed files. |
bzgrep | Used to call grep for bzip2 compressed files. |
bzip2 | A block-sorting file compressor used to shrink given files. |
bzless | Used to apply ‘less’ (show info one page at a time) to bzip2 compressed files. |
bzmore | Used to apply ‘more’ (an inferior version of less) to bzip2 compressed files. |
| |
Linux Commands – C | |
| |
Command | Description |
cal | Show calendar. |
cardctl | Used to control PCMCIA sockets and select configuration schemes. |
cardmgr | Keeps an eye on the added/removes sockets for PCMCIA devices. |
case | Execute a command conditionally by matching a pattern. |
cat | Used to concatenate files and print them on the screen. |
cc | GNU C and C++ compiler. |
cd | Used to change directory. |
cdda2wav | Used to rip a CD-ROM and make WAV file. |
cdparanoia | Record audio from CD more reliably using data-verification algorithms. |
cdrdao | Used to write all the content specified to a file to a CD all at once. |
cdrecord | Used to record data or audio compact discs. |
cfdisk | Show or change the disk partition table. |
chage | Used to change user password information. |
chattr | Used to change file attributes. |
chdir | Used to change active working directory. |
chfn | Used to change real user name and information. |
chgrp | Used to change group ownership for file. |
chkconfig | Manage execution of runlevel services. |
chmod | Change access permission for a file(s). |
chown | Change the owner or group for a file. |
chpasswd | Update password in a batch. |
chroot | Run a command with root privileges. |
chrt | Alter process attributed in real-time. |
chsh | Switch login shell. |
chvt | Change foreground virtual terminal. |
cksum | Perform a CRC checksum for files. |
clear | Used to clear the terminal window. |
cmp | Compare two files (byte by byte). |
col | Filter reverse (and half-reverse) line feeds from the input. |
colcrt | Filter nroff output for CRT previewing. |
colrm | Remove columns from the lines of a file. |
column | A utility that formats its input into columns. |
comm | Used to compare two sorted files line by line. |
command | Used to execute a command with arguments ignoring shell function named command. |
compress | Used to compress one or more file(s) and replacing the originals ones. |
continue | Resume the next iteration of a loop. |
cp | Copy contents of one file to another. |
cpio | Copy files from and to archives. |
cpp | GNU C language processor. |
cron | A daemon to execute scheduled commands. |
crond | Same work as cron. |
crontab | Manage crontab files (containing schedules commands) for users. |
csplit | Split a file into sections on the basis of context lines. |
ctags | Make a list of functions and macro names defined in a programming source file. |
cupsd | A scheduler for CUPS. |
curl | Used to transfer data from or to a server using supported protocols. |
cut | Used to remove sections from each line of a file(s). |
cvs | Concurrent Versions System. Used to track file versions, allow storage/retrieval of previous versions, and enables multiple users to work on the same file. |
| |
Linux Commands – D | |
| |
Command | Description |
date | Show system date and time. |
dc | Desk calculator utility. |
dd | Used to convert and copy a file, create disk clone, write disk headers, etc. |
ddrescue | Used to recover data from a crashed partition. |
deallocvt | Deallocates kernel memory for unused virtual consoles. |
debugfs | File system debugger for ext2/ext3/ext4 |
declare | Used to declare variables and assign attributes. |
depmod | Generate modules.dep and map files. |
devdump | Interactively displays the contents of device or file system ISO. |
df | Show disk usage. |
diff | Used to compare files line by line. |
diff3 | Compare three files line by line. |
dig | Domain Information Groper, a DNS lookup utility. |
dir | List the contents of a directory. |
dircolors | Set colors for ‘ls’ by altering the LS_COLORS environment variable. |
dirname | Display pathname after removing the last slash and characters thereafter. |
dirs | Show the list of remembered directories. |
disable | Restrict access to a printer. |
dlpsh | Interactive Desktop Link Protocol (DLP) shell for PalmOS. |
dmesg | Examine and control the kernel ring buffer. |
dnsdomainname | Show the DNS domain name of the system. |
dnssec-keygen | Generate encrypted Secure DNS keys for a given domain name. |
dnssec-makekeyset | Produce domain key set from one or more DNS security keys generated by dnssec-keygen. |
dnssec-signkey | Sign a secure DNS keyset with key signatures specified in the list of key-identifiers. |
dnssec-signzone | Sign a secure DNS zonefile with the signatures in the specified list of key-identifiers. |
doexec | Used to run an executable with an arbitrary argv list provided. |
domainname | Show or set the name of current NIS (Network Information Services) domain. |
dosfsck | Check and repair MS-DOS file systems. |
du | Show disk usage summary for a file(s). |
dump | Backup utility for ext2/ext3 file systems. |
dumpe2fs | Dump ext2/ext3/ext4 file systems. |
dumpkeys | Show information about the keyboard driver’s current translation tables. |
| |
Linux Commands – E | |
| |
Command | Desription |
e2fsck | Used to check ext2/ext3/ext4 file systems. |
e2image | Store important ext2/ext3/ext4 filesystem metadata to a file. |
e2label | Show or change the label on an ext2/ext3/ext4 filesystem. |
echo | Send input string(s) to standard output i.e. display text on the screen. |
ed | GNU Ed – a line-oriented text editor. |
edquota | Used to edit filesystem quotas using a text editor, such as vi. |
egrep | Search and display text matching a pattern. |
eject | Eject removable media. |
elvtune | Used to set latency in the elevator algorithm used to schedule I/O activities for specified block devices. |
emacs | Emacs text editor command line utility. |
enable | Used to enable/disable shell builtin commands. |
env | Run a command in a modified environment. Show/set/delete environment variables. |
envsubst | Substitute environment variable values in shell format strings. |
esd | Start the Enlightenment Sound Daemon (EsounD or esd). Enables multiple applications to access the same audio device simultaneously. |
esd-config | Manage EsounD configuration. |
esdcat | Use EsounD to send audio data from a specified file. |
esdctl | EsounD control program. |
esddsp | Used to reroute non-esd audio data to esd and control all the audio using esd. |
esdmon | Used to copy the sound being sent to a device. Also, send it to a secondary device. |
esdplay | Use EsounD system to play a file. |
esdrec | Use EsounD to record audio to a specified file. |
esdsample | Sample audio using esd. |
etags | Used to create a list of functions and macros from a programming source file. These etags are used by emacs. For vi, use ctags. |
ethtool | Used to query and control network driver and hardware settings. |
eval | Used to evaluate multiple commands or arguments are once. |
ex | Interactive command |
exec | An interactive line-based text editor. |
exit | Exit from the terminal. |
expand | Convert tabs into spaces in a given file and show the output. |
expect | An extension to the Tcl script, it’s used to automate interaction with other applications based on their expected output. |
export | Used to set an environment variable. |
expr | Evaluate expressions and display them on standard output. |
| |
Linux Commands – F | |
| |
Command | Description |
factor | Display prime factors of specified integer numbers. |
FALSE | Do nothing, unsuccessfully. Exit with a status code indicating failure. |
fc-cache | Make font information cache after scanning the directories. |
fc-list | Show the list of available fonts. |
fdformat | Do a low-level format on a floppy disk. |
fdisk | Make changes to the disk partition table. |
fetchmail | Fetch mail from mail servers and forward it to the local mail delivery system. |
fg | Used to send a job to the foreground. |
fgconsole | Display the number of the current virtual console. |
fgrep | Display lines from a file(s) that match a specified string. A variant of grep. |
file | Determine file type for a file. |
find | Do a file search in a directory hierarchy. |
finger | Display user data including the information listed in .plan and .project in each user’s home directory. |
fingerd | Provides a network interface for the finger program. |
flex | Generate programs that perform pattern-matching on text. |
fmt | Used to convert text to a specified width by filling lines and removing new lines, displaying the output. |
fold | Wrap input line to fit in a specified width. |
for | Expand words and run commands for each one in the resultant list. |
formail | Used to filter standard input into mailbox format. |
format | Used to format disks. |
free | Show free and used system memory. |
fsck | Check and repair a Linux file system |
ftp | File transfer protocol user interface. |
ftpd | FTP server process. |
function | Used to define function macros. |
fuser | Find and kill a process accessing a file. |
| |
Linux Commands – G | |
| |
Command | Description |
g++ | Run the g++ compiler. |
gawk | Used for pattern scanning and language processing. A GNU implementation of AWK language. |
gcc | A C and C++ compiler by GNU. |
gdb | A utility to debug programs and know about where it crashes. |
getent | Shows entries from Name Service Switch Libraries for specified keys. |
getkeycodes | Displays the kernel scancode-to-keycode mapping table. |
getopts | A utility to parse positional parameters. |
gpasswd | Allows an administrator to change group passwords. |
gpg | Enables encryption and signing services as per the OpenPGP standard. |
gpgsplit | Used to split an OpenPGP message into packets. |
gpgv | Used to verify OpenPGP signatures. |
gpm | It enables cut and paste functionality and a mouse server for the Linux console. |
gprof | Shows call graph profile data. |
grep | Searches input files for a given pattern and displays the relevant lines. |
groff | Serves as the front-end of the groff document formatting system. |
groffer | Displays groff files and man pages. |
groupadd | Used to add a new user group. |
groupdel | Used to remove a user group. |
groupmod | Used to modify a group definition. |
groups | Show the group(s) to which a user belongs. |
grpck | Verifies the integrity of group files. |
grpconv | Creates a gshadow file from a group or an already existing gshadow. |
gs | Invokes Ghostscript, and interpreter and previewer for Adobe’s PostScript and PDF languages. |
gunzip | A utility to compress/expand files. |
gzexe | Used compress executable files in place and have them automatically uncompress and run at a later stage. |
gzip | Same as gzip. |
| |
Linux Commands – H | |
| |
Command | Description |
halt | Command used to half the machine. |
hash | Shows the path for the commands executed in the shell. |
hdparm | Show/configure parameters for SATA/IDE devices. |
head | Shows first 10 lines from each specified file. |
help | Display’s help for a built-in command. |
hexdump | Shows specified file output in hexadecimal, octal, decimal, or ASCII format. |
history | Shows the command history. |
host | A utility to perform DNS lookups. |
hostid | Shows host’s numeric ID in hexadecimal format. |
hostname | Display/set the hostname of the system. |
htdigest | Manage the user authentication file used by the Apache web server. |
htop | An interactive process viewer for the command line. |
hwclock | Show or configure the system’s hardware clock. |
| |
Linux Commands – I | |
| |
Command | Description |
iconv | Convert text file from one encoding to another. |
id | Show user and group information for a specified user. |
if | Execute a command conditionally. |
ifconfig | Used to configure network interfaces. |
ifdown | Stops a network interface. |
ifup | Starts a network interface. |
imapd | An IMAP (Interactive Mail Access Protocol) server daemon. |
import | Capture an X server screen and saves it as an image. |
inetd | Extended internet services daemon, it starts the programs that provide internet services. |
info | Used to read the documentation in Info format. |
init | Systemd system and service manager. |
insmod | A program that inserts a module into the Linux kernel. |
install | Used to copy files to specified locations and set attributions during the install process. |
iostat | Shows statistics for CPU, I/O devices, partitions, network filesystems. |
ip | Display/manipulate routing, devices, policy, routing and tunnels. |
ipcrm | Used to remove System V interprocess communication (IPC) objects and associated data structures. |
ipcs | Show information on IPC facilities for which calling process has read access. |
iptables | Administration tool for IPv4 packet filtering and NAT. |
iptables-restore | Used to restore IP tables from data specified in the input or a file. |
iptables-save | Used to dump IP table contents to standard output. |
isodump | A utility that shows the content iso9660 images to verify the integrity of directory contents. |
isoinfo | A utility to perform directory like listings of iso9660 images. |
isosize | Show the length of an iso9660 filesystem contained in a specified file. |
isovfy | Verifies the integrity of an iso9660 image. |
ispell | A CLI-based spell-check utility. |
| |
Linux Commands – J | |
| |
Command | Description |
jobs | Show the list of active jobs and their status. |
join | For each pair of input lines, join them using a command field and display on standard output. |
| |
Linux Commands – K | |
| |
Command | Description |
kbd_mode | Set a keyboard mode. Without arguments, shows the current keyboard mode. |
kbdrate | Reset keyboard repeat rate and delay time. |
kill | Send a kill (termination) signal to one more processes. |
killall | Kills a process(es) running a specified command. |
killall5 | A SystemV killall command. Kills all the processes excluding the ones which it depends on. |
klogd | Control and prioritize the kernel messages to be displayed on the console, and log them through syslogd. |
kudzu | Used to detect new and enhanced hardware by comparing it with existing database. Only for RHEL and derivates. |
| |
Linux Commands – L | |
| |
Command | Description |
last | Shows a list of recent logins on the system by fetching data from /var/log/wtmp file. |
lastb | Shows the list of bad login attempts by fetching data from /var/log/btmp file. |
lastlog | Displays information about the most recent login of all users or a specified user. |
ld | The Unix linker, it combines archives and object files. It then puts them into one output file, resolving external references. |
ldconfig | Configure dynamic linker run-time bindings. |
ldd | Shows shared object dependencies. |
less | Displays contents of a file one page at a time. It’s advanced than more command. |
lesskey | Used to specify key bindings for less command. |
let | Used to perform integer artithmetic on shell variables. |
lftp | An FTP utility with extra features. |
lftpget | Uses lftop to retrieve HTTP, FTP, and other protocol URLs supported by lftp. |
link | Create links between two files. Similar to ln command. |
ln | Create links between files. Links can be hard (two names for the same file) or soft (a shortcut of the first file). |
loadkeys | Load keyboard translation tables. |
local | Used to create function variables. |
locale | Shows information about current or all locales. |
locate | Used to find files by their name. |
lockfile | Create semaphore file(s) which can be used to limit access to a file. |
logger | Make entries in the system log. |
login | Create a new session on the system. |
logname | Shows the login name of the current user. |
logout | Performs the logout operation by making changes to the utmp and wtmp files. |
logrotate | Used for automatic rotation, compression, removal, and mailing of system log files. |
look | Shows any lines in a file containing a given string in the beginning. |
losetup | Set up and control loop devices. |
lpadmin | Used to configure printer and class queues provided by CUPS (Common UNIX Printing System). |
lpc | Line printer control program, it provides limited control over CUPS printer and class queues. |
lpinfo | Shows the list of avaiable devices and drivers known to the CUPS server. |
lpmove | Move on or more printing jobs to a new destination. |
lpq | Shows current print queue status for a specified printer. |
lpr | Used to submit files for printing. |
lprint | Used to print a file. |
lprintd | Used to abort a print job. |
lprintq | List the print queue. |
lprm | Cancel print jobs. |
lpstat | Displays status information about current classes, jobs, and printers. |
ls | Shows the list of files in the current directory. |
lsattr | Shows file attributes on a Linux ext2 file system. |
lsblk | Lists information about all available or the specified block devices. |
lsmod | Show the status of modules in the Linux kernel. |
lsof | List open files. |
lspci | List all PCI devices. |
lsusb | List USB devices. |
| |
Linux Commands – M | |
| |
Command | Description |
m4 | Macro processor. |
mail | Utility to compose, receive, send, forward, and reply to emails. |
mailq | Shows to list all emails queued for delivery (sendmail queue). |
mailstats | Shows current mail statistics. |
mailto | Used to send mail with multimedia content in MIME format. |
make | Utility to maintain groups of programs, recompile them if needed. |
makedbm | Creates an NIS (Network Information Services) database map. |
makemap | Creates database maps used by the keyed map lookups in sendmail. |
man | Shows manual pages for Linux commands. |
manpath | Determine search path for manual pages. |
mattrib | Used to change MS-DOS file attribute flags. |
mbadblocks | Checks MD-DOS filesystems for bad blocks. |
mcat | Dump raw disk image. |
mcd | Used to change MS-DOS directory. |
mcopy | Used to copy MS-DOS files from or to Unix. |
md5sum | Used to check MD5 checksum for a file. |
mdel, mdeltree | Used to delete MS-DOS file. mdeltree recursively deletes MS-DOS directory and its contents. |
mdir | Used to display an MS-DOS directory. |
mdu | Used to display the amount of space occupied by an MS-DOS directory. |
merge | Three-way file merge. Includes all changes from file2 and file3 to file1. |
mesg | Allow/disallow osends to sedn write messages to your terminal. |
metamail | For sending and showing rich text or multimedia email using MIME typing metadata. |
metasend | An interface for sending non-text mail. |
mformat | Used to add an MS-DOS filesystem to a low-level formatted floppy disk. |
mimencode | Translate to/from MIME multimedia mail encoding formats. |
minfo | Display parameters of an MS-DOS filesystem. |
mkdir | Used to create directories. |
mkdosfs | Used to create an MS-DOS filesystem under Linux. |
mke2fs | Used create an ext2/ext3/ext4 filesystem. |
mkfifo | Used to create named pipes (FIFOs) with the given names. |
mkfs | Used to build a Linux filesystem on a hard disk partition. |
mkfs.ext3 | Same as mke2fs, create an ext3 Linux filesystem. |
mkisofs | Used to create an ISO9660/JOLIET/HFS hybrid filesystem. |
mklost+found | Create a lost+found directory on a mounted ext2 filesystem. |
mkmanifest | Makes a list of file names and their DOS 8.3 equivalent. |
mknod | Create a FIFO, block (buffered) special file, character (unbuffered) special file with the specified name. |
mkraid | Used to setup RAID device arrays. |
mkswap | Set up a Linux swap area. |
mktemp | Create a temporary file or directory. |
mlabel | Make an MD-DOS volume label. |
mmd | Make an MS-DOS subdirectory. |
mmount | Mount an MS-DOS disk. |
mmove | Move or rename an MS-DOS file or subdirectory. |
mmv | Mass move and rename files. |
modinfo | Show information about a Linux kernel module. |
modprobe | Add or remove modules from the Linux kernel. |
more | Display content of a file page-by-page. |
most | Browse or page through a text file. |
mount | Mount a filesystem. |
mountd | NFS mount daemon. |
mpartition | Partition an MS-DOS disk. |
mpg123 | Command-line mp3 player. |
mpg321 | Similar to mpg123. |
mrd | Remove an MS-DOS subdirectory. |
mren | Rename an existing MS-DOS file. |
mshowfat | Show FTA clusters allocated to a file. |
mt | Control magnetic tape drive operation. |
mtools | Utilities to access MS-DOS disks. |
mtoolstest | Tests and displays the mtools configuration files. |
mtr | A network diagnostic tool. |
mtype | Display contents of an MS-DOS file. |
mv | Move/rename files or directories. |
mzip | Change protection mode and eject disk on Zip/Jaz drive. |
| |
Linux Commands – N | |
| |
Command | Description |
named | Internet domain name server. |
namei | Follow a pathname until a terminal point is found. |
nameif | Name network interfaces based on MAC addresses. |
nc | Netcat utility. Arbitrary TCP and UDP connections and listens. |
netstat | Show network information. |
newaliases | Rebuilds mail alias database. |
newgrp | Log-in to a new group. |
newusers | Update/create new users in batch. |
nfsd | Special filesystem for controlling Linux NFS server. |
nfsstat | List NFS statistics. |
nice | Run a program with modified scheduling priority. |
nl | Show numbered line while displaying the contents of a file. |
nm | List symbols from object files. |
nohup | Run a command immune to hangups. |
notify-send | A program to send desktop notifications. |
nslookup | Used performs DNS queries. Read this article for more info. |
nsupdate | Dynamic DNS update utility. |
| |
Linux Commands – O | |
| |
Command | Description |
objcopy | Copy and translate object files. |
objdump | Display information from object files. |
od | Dump files in octal and other formats. |
op | Operator access, allows system administrators to grant users access to certain root operations that require superuser privileges. |
open | Open a file using its default application. |
openvt | Start a program on a new virtual terminal (VT). |
| |
Linux Commands – P | |
| |
Command | Description |
passwd | Change user password. |
paste | Merge lines of files. Write to standard output, TAB-separated lines consisting of sqentially correspnding lines from each file. |
patch | Apply a patchfile (containing differences listing by diff program) to an original file. |
pathchk | Check if file names are valid or portable. |
perl | Perl 5 language interpreter. |
pgrep | List process IDs matching the specified criteria among all the running processes. |
pidof | Find process ID of a running program. |
ping | Send ICMP ECHO_REQUEST to network hosts. |
pinky | Lightweight finger. |
pkill | Send kill signal to processes based on name and other attributes. |
pmap | Report memory map of a process. |
popd | Removes directory on the head of the directory stack and takes you to the new directory on the head. |
portmap | Converts RPC program numbers to IP port numbers. |
poweroff | Shuts down the machine. |
pppd | Point-to-point protocol daemon. |
pr | Convert (column or paginate) text files for printing. |
praliases | Prints the current system mail aliases. |
printcap | Printer capability database. |
printenv | Show values of all or specified environment variables. |
printf | Show arguments formatted according to a specified format. |
ps | Report a snapshot of the current processes. |
ptx | Produce a permuted index of file contents. |
pushd | Appends a given directory name to the head of the stack and then cd to the given directory. |
pv | Monitor the progress of data through a pipe. |
pwck | Verify integrity of password files. |
pwconv | Creates shadow from passwd and an optionally existing shadow. |
pwd | Show current directory. |
python | Run Python 2.X instance. |
| |
Linux Commands – Q | |
| |
Command | Description |
quota | Shows disk usage, and space limits for a user or group. Without arguments, only shows user quotas. |
quotacheck | Used to scan a file system for disk usage. |
quotactl | Make changes to disk quotas. |
quotaoff | Enable enforcement of filesystem quotas. |
quotaon | Disable enforcement of filesystem quotas. |
quotastats | Shows the report of quota system statistics gathered from the kernel. |
| |
Linux Commands – R | |
| |
Command | Description |
raidstart | Start/stop RAID devices. |
ram | RAM disk device used to access the RAM disk in raw mode. |
ramsize | Show usage information for the RAM disk. |
ranlib | Generate index to the contents of an archive and store it in the archive. |
rar | Create and manage RAR file in Linux. |
rarpd | Respond to Reverse Address Resolution Protocol (RARP) requests. |
rcp | Remote copy command to copy files between remote computers. |
rdate | Set system date and time by fetching information from a remote machine. |
rdev | Set or query RAM disk size, image root device, or video mode. |
rdist | Remote file distribution client, maintains identical file copies over multiple hosts. |
rdistd | Start the rdist server. |
read | Read from a file descriptor. |
readarray | Read lines from a file into an array variable. |
readcd | Read/write compact disks. |
readelf | Shows information about ELF (Executable and Linkable fomrat) files. |
readlink | Display value of a symbolic link or canonical file name. |
readonly | Mark functions and variables as read-only. |
reboot | Restart the machine. |
reject | Accept/reject print jobs sent to a specified destination. |
remsync | Synchronize remote files over email. |
rename | Rename one or more files. |
renice | Change priority of active processes. |
repquota | Report disk usage and quotas for a specified filesystem. |
reset | Reinitialize the terminal. |
resize2fs | Used to resize ext2/ext3/ext4 file systems. |
restore | Restore files from a backup created using dump. |
return | Exit a shell function. |
rev | Show contents of a file, reversing the order of characters in every line. |
rexec | Remote execution client for exec server. |
rexecd | Remote execution server. |
richtext | View “richtext” on an ASCII terminal. |
rlogin | Used to connect a local host system with a remote host. |
rlogind | Acts as the server for rlogin. It facilitates remote login, and authentication based on privileged port numbers from trusted hosts. |
rm | Removes specified files and directories (not by default). |
rmail | Handle remote mail received via uucp. |
rmdir | Used to remove empty directories. |
rmmod | A program to remove modules from Linux kernel. |
rndc | Name server control utility. Send command to a BIND DNS server over a TCP connection. |
rootflags | Show/set flags for the kernel image. |
route | Show/change IP routing table. |
routed | A daemon, invoked at boot time, to manage internet routing tables. |
rpcgen | An RPC protocol compiler. Parse a file written in the RPC language. |
rpcinfo | Shows RPC information. Makes an RPC call to an RPC server and reports the findings. |
rpm | A package manager for linux distributions. Originally developed for RedHat Linux. |
rsh | Remote shell. Connects to a specified host and executes commands. |
rshd | A daemon that acts as a server for rsh and rcp commands. |
rsync | A versitile to for copying files remotely and locally. |
runlevel | Shows previous and current SysV runlevel. |
rup | Remote status display. Shows current system status for all or specified hosts on the local network. |
ruptime | Shows uptime and login details of the machines on the local network. |
rusers | Shows the list of the users logged-in to the host or on all machines on the local network. |
rusersd | The rsuerd daemon acts as a server that responds to the queries from rsuers command. |
rwall | Sends messages to all users on the local network. |
rwho | Reports who is logged-in to the hosts on the local network. |
rwhod | Acts as a server for rwho and ruptime commands. |
| |
Linux Commands – S | |
| |
Command | Description |
sane-find-scanner | Find SCSI and USB scanner and determine their device files. |
scanadf | Retrieve multiple images from a scanner equipped with an automatic document feeder (ADF). |
scanimage | Read images from image acquisition devices (scanner or camera) and display on standard output in PNM (Portable aNyMap) format. |
scp | Copy files between hosts on a network securely using SSH. |
screen | A window manager that enables multiple pseudo-terminals with the help of ANSI/VT100 terminal emulation. |
script | Used to make a typescript of everything displayed on the screen during a terminal session. |
sdiff | Shows two files side-by-side and highlights the differences. |
sed | Stream editor for filtering and transforming text (from a file or a pipe input). |
select | Synchronous I/O multiplexing. |
sendmail | It’s a mail router or an MTA (Mail Transfer Agent). sendmail support can send a mail to one or more recepients using necessary protocols. |
sensors | Shows the current readings of all sensor chips. |
seq | Displays an incremental sequence of numbers from first to last. |
set | Used to manipulate shell variables and functions. |
setfdprm | Sets floppy disk parameters as provided by the user. |
setkeycodes | Load kernel scancode-to-keycode mapping table entries. |
setleds | Show/change LED light settings of the keyboard. |
setmetamode | Define keyboard meta key handling. Without arguments, shows current meta key mode. |
setquota | Set disk quotas for users and groups. |
setsid | Run a program in a new session. |
setterm | Set terminal attributes. |
sftp | Secure File Transfer program. |
sh | Command interpreter (shell) utility. |
sha1sum | Compute and check 160-bit SHA1 checksum to verify file integrity. |
shift | Shift positional parameters. |
shopt | Shell options. |
showkey | Examines codes sent by the keyboard displays them in printable form. |
showmount | Shows information about NFS server mount on the host. |
shred | Overwrite a file to hide its content (optionally delete it), making it harder to recover it. |
shutdown | Power-off the machine. |
size | Lists section size and the total size of a specified file. |
skill | Send a signal to processes. |
slabtop | Show kernel slab cache information in real-time. |
slattach | Attack a network interface to a serial line. |
sleep | Suspend execution for a specified amount of time (in seconds). |
slocate | Display matches by searching filename databases. Takes ownership and file permission into consideration. |
snice | Reset priority for processes. |
sort | Sort lines of text files. |
source | Run commands from a specified file. |
split | Split a file into pieces of fixed size. |
ss | Display socket statistics, similar to netstat. |
ssh | An SSH client for logging in to a remote machine. It provides encrypted communication between the hosts. |
ssh-add | Adds private key identities to the authentication agent. |
ssh-agent | It holds private keys used for public key authentication. |
ssh-keygen | It generates, manages, converts authentication keys for ssh. |
ssh-keyscan | Gather ssh public keys. |
sshd | Server for the ssh program. |
stat | Display file or filesystem status. |
statd | A daemon that listens for reboot notifications from other hosts, and manages the list of hosts to be notified when the local system reboots. |
strace | Trace system calls and signals. |
strfile | Create a random access file for storing strings. |
strings | Search a specified file and prints any printable strings with at least four characters and followed by an unprintable character. |
strip | Discard symbols from object files. |
stty | Change and print terminal line settings. |
su | Change user ID or become superuser. |
sudo | Execute a command as superuser. |
sum | Checksum and count the block in a file. |
suspend | Suspend the execution of the current shell. |
swapoff | Disable devices for paging and swapping. |
swapon | Enable devices for paging and swapping. |
symlink | Create a symbolic link to a file. |
sync | Synchronize cached writes to persistent storage. |
sysctl | Configure kernel parameters at runtime. |
sysklogd | Linux system logging utilities. Provides syslogd and klogd functionalities. |
syslogd | Read and log system messages to the system console and log files. |
| |
Linux Commands – T | |
| |
Command | Description |
tac | Concatenate and print files in reverse order. Opposite of cat command. |
tail | Show the last 10 lines of each specified file(s). |
tailf | Follow the growth of a log file. (Deprecated command) |
talk | A two-way screen-oriented communication utility that allows two user to exchange messages simulateneously. |
talkd | A remote user communication server for talk. |
tar | GNU version of the tar archiving utility. Used to store and extract multiple files from a single archive. |
taskset | Set/retrieve a process’s CPU affinity. |
tcpd | Access control utility for internet services. |
tcpdump | Dump traffic on network. Displays a description of the contents of packets on a network interface that match the boolean expression. |
tcpslice | Extract pieces of tcpdump files or merge them. |
tee | Read from standard input and write to standard output and files. |
telinit | Change SysV runlevel. |
telnet | Telnet protocol user interface. Used to interact with another host using telnet. |
telnetd | A server for the telnet protocol. |
test | Check file type and compare values. |
tftp | User interface to the internet TFTP (Trivial File Transfer Protocol). |
tftpd | TFTP server. |
time | Run programs and summarize system resource usage. |
timeout | Execute a command with a time limit. |
times | Shows accumulated user and system times for the shell and it’s child processes. |
tload | Shows a graph of the current system load average to the specified tty. |
tmpwatch | Recursively remove files and directories which haven’t been accessed for the specified period of time. |
top | Displays real-time view of processes running on the system. |
touch | Change file access and modification times. |
tput | Modify terminal-dependent capabilities, color, etc. |
tr | Translate, squeeze, or delete characters from standard input and display on standard output. |
tracepath | Traces path to a network host discovering MTU (Maximum Transmission Unit) along this path. |
traceroute | Traces the route taken by the packets to reach the network host. |
trap | Trap function responds to hardware signals. It defines and creates handlers to run when the shell receives signals. |
troff | The troff processor of the groff text formatting system. |
TRUE | Exit with a status code indicating success. |
tset | Initialize terminal. |
tsort | Perform topological sort. |
tty | Display the filename of the terminal connected to standard input. |
tune2fs | Adjust tunable filesystem parameters on ext2/ext3/ext4 filesystems. |
tunelp | Set various parameters for the line printer devices. |
type | Write a description for a command type. |
| |
Linux Commands – U | |
| |
Command | Description |
ul | Underline text. |
ulimit | Get and set user limits for the calling process. |
umask | Set file mode creation mask. |
umount | Unmount specified file systems. |
unalias | Remove alias definitions for specified alias names. |
uname | Show system information. |
uncompress | Uncompress the files compressed with the compress command. |
unexpand | Convert spaces to tabs for a specified file. |
unicode_start | Put keyboard and console in Unicode mode. |
unicode_stop | Revert keyboard and console from Unicode mode. |
uniq | Report or omit repeating lines. |
units | Convert units from one scalar to another. |
unrar | Extract files from a RAR archive. |
unset | Remove variable or function names. |
unshar | Unpack shell archive scripts. |
until | Execute command until a given condition is true. |
uptime | Tell how long the system has been running. |
useradd | Create a new user or update default user information. |
userdel | Delete a user account and related files. |
usermod | Modify a user account. |
users | Show the list of active users on the machine. |
usleep | Suspend execution for microsecond intervals. |
uudecode | Decode a binary file. |
uuencode | Encode a binary file. |
uuidgen | Created a new UUID (Universally Unique Identifier) table. |
| |
Linux Commands – V | |
| |
Command | Description |
vdir | Same as ls -l -b. Verbosely list directory contents. |
vi | A text editor utility. |
vidmode | Set the video mode for a kernel image. Displays current mode value without arguments. Alternative: rdev -v |
vim | Vi Improved, a text-based editor which is a successor to vi. |
vmstat | Shows information about processes, memory, paging, block IO, traps, disks, and CPU activity. |
volname | Returns volume name for a device formatted with an ISO-9660 filesystem. For example, CD-ROM. |
| |
Linux Commands – W | |
| |
Command | Description |
w | Show who is logged-on and what they’re doing. |
wait | Waits for a specified process ID(s) to terminate and returns the termination status. |
wall | Display a message on the terminals all the users who are currently logged-in. |
warnquota | Send mail to the users who’ve exceeded their disk quota soft limit. |
watch | Runs commands repeatedly until interrupted and shows their output and errors. |
wc | Print newline, word, and byte count for each of the specified files. |
wget | A non-interactive file download utility. |
whatis | Display one line manual page descriptions. |
whereis | Locate the binary, source, and man page files for a command. |
which | For a given command, lists the pathnames for the files which would be executed when the command runs. |
while | Conditionally execute commands (while loop). |
who | Shows who is logged on. |
whoami | Displays the username tied to the current effective user ID. |
whois | Looks for an object in a WHOIS database |
write | Display a message on other user’s terminal. |
| |
Linux Commands – X | |
| |
Command | Description |
xargs | Runs a command using initial arguments and then reads remaining arguments from standard input. |
xdg-open | Used to open a file or URL in an application preferred by the user. |
xinetd | Extended internet services daemon. Works similar to inetd. |
xz | Compress/ Decompress .xz and .lzma files. |
| |
Linux Commands – Y | |
| |
Command | Description |
yacc | Yet Another Compiler Compiler, a GNU Project parser generator. |
yes | Repeatedly output a line with a specified string(s) until killed. |
ypbind | A daemon that helps client processes to connect to an NIS server. |
ypcat | Shows the NIS map (or database) for the specified MapName parameter. |
ypinit | Sets up NIS maps on an NIS server. |
ypmatch | Shows values for specified keys from an NIS map. |
yppasswd | Change NIS login password. |
yppasswdd | Acts as a server for the yppasswd command. Receives and executes requests. |
yppoll | Shows the ID number or version of NIS map currently used on the NIS server. |
yppush | Forces slave NIS servers to copy updated NIS maps. |
ypserv | A daemon activated at system startup. It looks for information in local NIS maps. |
ypset | Point a client (running ypbind) to a specifc server (running ypserv). |
yptest | Calls various functions to check the configuration of NIS services. |
ypwhich | Shows the hostname for NIS server or master server for a given map. |
ypxfr | Transfers NIS server map from server to a local host. |
| |
Linux Commands – Z | |
| |
Command | Description |
zcat | Used to compress/uncompress files. Similar to gzip |
zcmp | Compare compressed files. |
zdiff | Compare compressed files line by line. |
zdump | Displays time for the timezone mentioned. |
zforce | Adds .gz extension to all gzipped files. |
zgrep | Performs grep on compressed files. |
zic | Creates time conversion information files using the specified input files. |
zip | A file compression and packaging utility. |
zless | Displays information of a compressed file (using less command) on the terminal one screen at a time. |
zmore | Displays output of a compressed file (using more command) on the terminal one page at a time. |
znew | Recompress .z files to .gz. files. |