Common SSH Commands - Linux Shell Commands Published: Nov 08, 2003

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An easy to follow guide of command commands in SSH or linux shell commands, with an explination of what they are used for and an example of their use.

ear.

Updated: Jan 19, 2007: Added some new ssh commands for the linux shell.

We've put together some of the more frequently used SSH commands or linux shell commands, and organized them by name so you can easily find a command, their description and how to use it. This guide will continue to be updated and should not be considered a complete list of SSH commands or linux shell commands, but commands, we found, often used. If you would like to add to this guide, please email us and let us know.

Common SSH Commands or Linux Shell Commands,
ls : list files/directories in a directory, comparable to dir in windows/dos.
ls -al : shows all files (including ones that start with a period), directories, and details attributes for each file.

cd : change directory · · cd /usr/local/apache : go to /usr/local/apache/ directory
cd ~ : go to your home directory
cd - : go to the last directory you were in
cd .. : go up a directory cat : print file contents to the screen

cat filename.txt : cat the contents of filename.txt to your screen

chmod: changes file access permissions
The set of 3 go in this order from left to right:
USER - GROUP - EVERONE

0 = --- No permission
1 = --X Execute only
2 = -W- Write only
3 = -WX Write and execute
4 = R-- Read only
5 = R-X Read and execute
6 = RW- Read and write
7 = RWX Read, write and execute

Usage:
chmod numberpermissions filename

chmod 000 : No one can access
chmod 644: Usually for HTML pages
chmod 755: Usually for CGI scripts

chown: changes file ownership permissions
The set of 2 go in this order from left to right:
USER - GROUP

chown root myfile.txt : Changes the owner of the file to root
chown root.root myfile.txt : Changes the owner and group of the file to root

tail : like cat, but only reads the end of the file
tail /var/log/messages : see the last 20 (by default) lines of /var/log/messages
tail -f /var/log/messages : watch the file continuously, while it's being updated
tail -200 /var/log/messages : print the last 200 lines of the file to the screen

more : like cat, but opens the file one screen at a time rather than all at once
more /etc/userdomains : browse through the userdomains file. hit Spaceto go to the next page, q to quit

pico : friendly, easy to use file editor
pico /home/burst/public_html/index.html : edit the index page for the user's website.

File Editing with VI ssh commands
vi : another editor, tons of features, harder to use at first than pico
vi /home/burst/public_html/index.html : edit the index page for the user's website.
Whie in the vi program you can use the following useful commands, you will need to hit SHIFT + : to go into command mode

:q! : This force quits the file without saving and exits vi
:w : This writes the file to disk, saves it
:wq : This saves the file to disk and exists vi
:LINENUMBER : EG :25 : Takes you to line 25 within the file
:$ : Takes you to the last line of the file
:0 : Takes you to the first line of the file

grep : looks for patterns in files
grep root /etc/passwd : shows all matches of root in /etc/passwd
grep -v root /etc/passwd : shows all lines that do not match root

ln : create's "links" between files and directories
ln -s /usr/local/apache/conf/httpd.conf /etc/httpd.conf : Now you can edit /etc/httpd.conf rather than the original. changes will affect the orginal, however you can delete the link and it will not delete the original.

last : shows who logged in and when
last -20 : shows only the last 20 logins
last -20 -a : shows last 20 logins, with the hostname in the last field

w : shows who is currently logged in and where they are logged in from.
who : This also shows who is on the server in an shell.

netstat : shows all current network connections.
netstat -an : shows all connections to the server, the source and destination ips and ports.
netstat -rn : shows routing table for all ips bound to the server.

top : shows live system processes in a nice table, memory information, uptime and other useful info. This is excellent for managing your system processes, resources and ensure everything is working fine and your server isn't bogged down.
top then type Shift + M to sort by memory usage or Shift + P to sort by CPU usage

ps: ps is short for process status, which is similar to the top command. It's used to show currently running processes and their PID.
A process ID is a unique number that identifies a process, with that you can kill or terminate a running program on your server (see kill command).
ps U username : shows processes for a certain user
ps aux : shows all system processes
ps aux --forest : shows all system processes like the above but organizes in a hierarchy that's very useful!

touch : create an empty file
touch /home/burst/public_html/404.html : create an empty file called 404.html in the directory /home/burst/public_html/

file : attempts to guess what type of file a file is by looking at it's content.
file * : prints out a list of all files/directories in a directory

du : shows disk usage.
du -sh : shows a summary, in human-readble form, of total disk space used in the current directory, including subdirectories.
du -sh * : same thing, but for each file and directory. helpful when finding large files taking up space.

wc : word count
wc -l filename.txt : tells how many lines are in filename.txt

cp : copy a file
cp filename filename.backup : copies filename to filename.backup
cp -a /home/burst/new_design/* /home/burst/public_html/ : copies all files, retaining permissions form one directory to another.
cp -av * ../newdir : Copies all files and directories recurrsively in the current directory INTO newdir

mv : Move a file command
mv oldfilename newfilename : Move a file or directory from oldfilename to newfilename

rm : delete a file
rm filename.txt : deletes filename.txt, will more than likely ask if you really want to delete it
rm -f filename.txt : deletes filename.txt, will not ask for confirmation before deleting.
rm -rf tmp/ : recursively deletes the directory tmp, and all files in it, including subdirectories. BE VERY CAREFULL WITH THIS COMMAND!!!

TAR: Creating and Extracting .tar.gz and .tar files
tar -zxvf file.tar.gz : Extracts the file
tar -xvf file.tar : Extracts the file
tar -cf archive.tar contents/ : Takes everything from contents/ and puts it into archive.tar
gzip -d filename.gz : Decompress the file, extract it

ZIP Files: Extracting .zip files shell command
unzip file.zip

Firewall - iptables commands
iptables -I INPUT -s IPADDRESSHERE -j DROP : This command stops any connections from the IP address
iptables -L : List all rules in iptables
iptables -F : Flushes all iptables rules (clears the firewall)
iptables --save : Saves the currenty ruleset in memory to disk
service iptables restart : Restarts iptables

Apache Shell Commands
httpd -v : Outputs the build date and version of the Apache server.
httpd -l : Lists compiled in Apache modules
httpd status : Only works if mod_status is enabled and shows a page of active connections
service httpd restart : Restarted Apache web server

MySQL Shell Commands
mysqladmin processlist : Shows active mysql connections and queries
mysqladmin drop databasenamehere : Drops/deletes the selected database
mysqladmin create databasenamehere : Creates a mysql database

Restore MySQL Database Shell Command
mysql -u username -p password databasename < databasefile.sql : Restores a MySQL database from databasefile.sql

Backup MySQL Database Shell Command
mysqldump -u username -p password databasename > databasefile.sql : Backup MySQL database to databasefile.sql

kill: terminate a system process
kill -9 PID EG: kill -9 431
kill PID EG: kill 10550
Use top or ps ux to get system PIDs (Process IDs)

EG:

PID	TTY	TIME	COMMAND
10550	pts/3	0:01	/bin/csh
10574	pts/4	0:02	/bin/csh
10590	pts/4	0:09	APP

Each line represents one process, with a process being loosely defined as a running instance of a program. The column headed PID (process ID) shows the assigned process numbers of the processes. The heading COMMAND shows the location of the executed process.

Putting commands together
Often you will find you need to use different commands on the same line. Here are some examples. Note that the | character is called a pipe, it takes date from one program and pipes it to another.
> means create a new file, overwriting any content already there.
>> means tp append data to a file, creating a newone if it doesn not already exist.
< send input from a file back into a command.

grep User /usr/local/apache/conf/httpd.conf |more
This will dump all lines that match User from the httpd.conf, then print the results to your screen one page at a time.

last -a > /root/lastlogins.tmp
This will print all the current login history to a file called lastlogins.tmp in /root/

tail -10000 /var/log/exim_mainlog |grep domain.com |more
This will grab the last 10,000 lines from /var/log/exim_mainlog, find all occurances of domain.com (the period represents 'anything',
-- comment it out with a so it will be interpretted literally), then send it to your screen page by page.

netstat -an |grep :80 |wc -l
Show how many active connections there are to apache (httpd runs on port 80)

mysqladmin processlist |wc -l
Show how many current open connections there are to mysql

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Comments (93)

chris 15:02, November 15, 2003

Re: vi

you should include how to stop/quit and alos kill "vi" via the command line as this happens more than it should and if left running it will use most srv CPU recources.
Jia 19:31, January 9, 2004

If I have to type in several commands repeatedly, is there a button I can press to automatically have them typed on the command line instead of having to repeatedly type the same thing over and over again?
Dhiraj 11:44, January 29, 2004

yes Jai

Pressing the upper arrow key will scroll through all the previously typed commands.

Hope this helps.
Boris 11:40, February 11, 2004

Excellent for n00bs...
tt 14:18, August 16, 2004

Ctrl plus C works well to stop alot of srolling.. 
 
Hope it helps 
 
thanks great site GUYS
c.jayanthi 15:51, September 9, 2004

it is very usefull for beginners.if you put all these information with example , it will be very nice.
mafiaboy 10:56, October 2, 2004

move: move or rename file
mateen 05:48, October 3, 2004

Dear Sir my name is Mateen so i am from afghanistan so now a days i installed linux server so I face tothe problem concerning the ACL in Linux 9.0 server if you help me and in Access control if you help me in this regard I will be appreciate you . 
 
I am looking forward for you response 
 
Kind regards 
Mateen
Andrius 19:02, November 27, 2004

Greetings 
 
What is the command to know what files are in use by particular user. 
 
I ask this coz I want to know what files do belong to me in my server (I am not an admin) 
 
And I would like to know how much hdd space all my files take..
floating carcass 14:10, November 29, 2004

hi, 
I would like to know what ports are active/being used currently. Is there some way other than nmap... 
fc
eddie 21:18, January 6, 2005

Andrius - simply type ll 
 
that's (LL)
kim 05:41, February 3, 2005

what is the command to create a directory? 
mk dir is not working for me...
frank 17:32, February 23, 2005

Hi, what command can be used to recover the deleted files. Some times i accidentally issue a command in a certain directory, thinking that i am in another directory working on files that i don't like, only to realize when i have deleted all files that directort. 
I would like to know it.....
Andy 03:35, April 3, 2005

Hi, I have a php script that optimizes/cleans my database and I was wondering what command I would use to run it automatically using a cron. I tried using cat but all that did was send me the source code to the file. (I use cpanel)
niXin 08:17, April 14, 2005

Hi - Im using FreeBSD, I have 6 colums of data in mail dir . I wanna check witch mailbox is the biggest eg: ls mailbox | sort -4 hope it's clear ...:) sorry if it's not
newbie 15:05, May 7, 2005

Floating carcass, are you using mk dir with a space between mk and dir? if so, it's just one string: mkdir
Vijay Modi 07:36, August 6, 2005

Very Good Article
karunakar 11:02, August 11, 2005

last -a > /root/lastlogins.tmp
Computer Guru 12:17, August 11, 2005

Great article for the n00bs, good job.. 
 
Can't believe you forgot CHOWN and CHMOD!!!!! 
 
The most important commands for most people doing uploads and installing ready-made scripts... CHOWN sets the owner of a file, folder, directory, etc. 
 
CHMOD sets the permissions... 
 
To find out what CHMOD permissions you need go to NeoSmart.net/DC.htm and get CHMOD-Win, which tells you which CHMOD number gives you the settings you need in plain text... 
 
Other than that, cheers!
L. Young 02:13, August 19, 2005

I'm a webhost, is SSH a easy system to use for hacking in our servers? 
 
also, is there any logs made of logins to SSH? 
 
can you email me with the answers, and if anyone wants to test security on our servers in return for hosting, etc? 
 
Cheers, 
Liam
darkangel 16:04, October 5, 2005

I would like a ssh command that could show me the traffic on the server!!
Philip Snyder 23:51, October 26, 2005

This is kind of a more advanced problem, but one I'm sure everyone will run into at one point or another. I do web development on a linux box with apache serving from another box behind a firewall. I can ssh TO the server, but not vice-versa. 
 
On my server, my php code spits out debug messages and error messages to a couple different log files. I want to tail these log files on my dev machine so I can watch the output while I develop. If I were content with just using tail, I could do the following: 
 
ssh user@server tail -f logs/my.log 
 
However, I want to use multitail (which allows regex generated color highlighting, etc)... and multitail is only installed on my dev machine. 
 
I know this can be done, but its not particularly easy. Personally, I'm still working on it -- if anyone knows how, let me know. Otherwise, I'll figure it out and post it here. ;) I'm looking at ssh w/ pipes for the solution right now.. so here's how you make a pipe (think of it like a water pipe... the first drops of water in are the first drops of water out the other end -- hence the fifo part of mkfifo): 
 
% mkfifo my.pipe
Anoop PK 08:34, November 8, 2005

Great !! Very Helpful
brindha 12:43, December 21, 2005

goood , add some more to the archieve
Jordan 04:21, December 25, 2005

That made no sense
kerk 05:50, January 19, 2006

is there a command to back up a mysql table?
sagar 15:12, February 6, 2006

Very Good Article
jhon 03:53, March 6, 2006

id is one of the best collection of commands of shh 
 
thanks.
adeyemi 20:41, March 27, 2006

hello, 
thanks for the oppotunity giving to us by reading some of this few dumps command online. pls sir i will like you to send me more command basically on unix system.
sandy 19:42, April 12, 2006

Nice
goamind 18:19, April 14, 2006

Great article! 
But I want to know the command for uploading my files to a remote server that I connected with using 
ssh -l user_name domain.com
Steve 10:40, April 27, 2006

To run a php script on a linux server that has lynx (a text based web browser) 
 
* * * * * lynx -dump http://yoursite.com/cron.php
Aram 00:05, June 4, 2006

I need help on the part where i'm in the vi server.cfg. I've edited everything in there except the part where i need to SAVE it. PleasE HELP ME !!!
fani 11:33, June 12, 2006

How to downlaod a file from a remote system using ssh. 
Actually i ssh'd into a system and i need a file to be downloaded on my pc or any other computer, I dont have any ftp server running on my pc and the system running sshd don't as the ftp either. what are the days to download the file
selva 05:58, June 23, 2006

It is very usefull for beginners.
Jack 02:33, June 29, 2006

As a newb to SSH usage on my servers I found some of these commands very helpfull (Thanks) 
 
I'm still searching for one command and would appreciate if anyone can help me out. 
 
I'm installing a site which is packed in filename.tar.gz , I unpack .tar without a problem but cant find a command to unpack from .gz 
 
Thanks in advance.
Ghzanfar 08:13, July 1, 2006

Its Nice effort for all of Linux Lovers. But i've a problem that i want to get those commands which perform the same function on two or more shells of linux but their name is different. If some one can help?
Paul 18:44, July 21, 2006

Great stuff! Found exactly what I was looking for. 
 
I esp. like this article/tutorial because it contains the BASIC stuff that a person need ;)
Ben Faust 22:44, August 9, 2006

The answer to the question of running a PHP script in a CRON: 
 
php /absolute/path/to/script.php
james gideon 10:06, August 13, 2006

 
Hi, 
 
Above listed command are very usefful for biggenner's,Please give more with examples like how they used in sever. 
 
Thanks.
Praveen 06:16, August 24, 2006

Yes, very nice commands for new user which I am. These commands are very helpful. Pls send me more basic and commands which are used on newtork. 
 
thanks
Kodiak 08:00, August 24, 2006

Thanks for this! Very helpful for this newbie. The article that referred me here had all sorts of errors - this one's nice and clean (apart from that one apostrophe: "file : attempts to guess what type of file a file is by looking at it's content" - it's should be its...) 
 
Thanks!
joey 21:27, October 14, 2006

I haven't a clue about all this- I'm just starting out with what all the jargon means for personal server management purposes. I hope a year from now I'm well acquainted with this field and will be laughing at how little I knew!
Karl 17:51, January 12, 2007

Samne problem as Aram here... i can get into Vi (vim) and create the file but how do i save the file and exit without leaving the file in the swapfile. Do you have a list of te commands used in vim editor? 
 
Regards.
danc 21:46, January 17, 2007

who knows how i can send messages through ssh console to the other user logged on a server also with ssh console. i know it can be done because i did it some time ago but i forgot and now i can't find out how.
Steve 22:22, January 19, 2007

Thanks for the feedback everyone, I've updated the SSH commands including many of the things you mentioned int the comments. 
 
Cheers
kari 18:06, February 23, 2007

I also had a hard time w/ the vi section. A quick google search lead me to this site: http://www.cs.colostate.edu/helpdocs/vi.html 
<esc> key will bring you out of insert mode, then you can enter the file commands (i.e. :wq) to save and whatnot.
Amit 22:42, March 9, 2007

Simpy great!!
soheil shahabi 23:48, April 5, 2007

Very nice, very basic yet vey useful, if would be nice if it was updated in a way and more things were added.
ndina 14:30, April 20, 2007

simpy and greet
spayced 01:19, June 24, 2007

very useful. except touch isn't specifically made for creating files, it's use is for updating the last modified timestamp. It's just a coincidence updating the timestamp for a nonexistant file creates the file :P
Nirmal 09:24, July 30, 2007

Very usful for starters, 
 
I just brought VDS server, and got SSH, and this is gonna be very much helpful for me! 
 
Cheers!
joey 09:23, August 14, 2007

Your site is great!
josh 13:22, August 26, 2007

kim the command is mkdir no spacing
sadman 15:54, October 5, 2007

nice tutorial, a building block for mastery... Ü
amrita 09:28, October 31, 2007

it's really great
Lê Quang Nhật Anh 17:47, November 25, 2007

Thanks a lot for this
deliq 14:28, December 19, 2007

thank you ! Thats very Helpfull for me !
kandrei 20:02, January 1, 2008

power corrupted my mail server and i lost all my old mails on the system. i secured users mail directories and my system configs. After reinstallation, I could only manage to get mails in their new mails folder en couldnot get the old ones how can i recover the old mails ?
amir.mozaffari 20:50, January 4, 2008

I Need Help In SSH And SQUID 
tnak you .
fahad 14:17, January 22, 2008

Thanks a lot for this
Zafar 07:27, January 31, 2008

Goods Commands For Initials.
Jason 00:08, February 17, 2008

I was actually trying to figure out how to create a folder, then create a file, and stuff like that.
brahmam 10:15, February 18, 2008

i have always been thankful to you.Because it is very much help to me. Please add some more commands to this web. Ok
kro 11:22, April 18, 2008

HOW DO I CLOSE A PROGRAM I JUST EXECUTED USING SSH TO MY IPHONE??
Mohan G 11:56, May 13, 2008

Good Site ! 
Provides lot of info for the new bi's !! 
:)
kay 19:58, May 27, 2008

********************************* 
 
********************************* 
 
Hi, 
 
I had to pay for a private server because I own many websites but I don't know how to find which domains put high load on the server when it happens, can you tell me what to do or where to find a tutorial about this ? 
 
 
Thanks. 
 
 
********************************* 
 
*********************************
rafiq 11:33, June 9, 2008

********************** 
Hi, 
This Site Is Very Helpfull For The Begainers 
Thanks A Lot
rekha 05:15, July 10, 2008

Very good method of explaining.Post some more details regarding Mysql.
santa 17:54, September 2, 2008

How can I download a file from my server to my PC using SSH?
olive 04:57, September 18, 2008

Can anyone specify the syntax how to set a .swf file in a cron scheduler. Whether its possible to set swf in a cron
hellu 11:28, September 23, 2008

Hi, 
 
I found this site very helpful as a new beginner. 
thanks a lot.
jeya 06:51, February 9, 2009

hi.. 
this is very very useful for the beginners .but still more commands can be added to make it best.
Viperdh 19:47, May 7, 2009

Very nice, one of the best lists I could find :) 
 
Thanks for taking the time to put it together. 
 
I've bookmarked it and I'm sure I'll be using it a few times while I get the hang of linux again :)
Divya 07:25, July 15, 2009

Very good aticle
Pankaj Sharma 08:04, August 13, 2009

Great Thanks 
Your website is great
Dustin 14:33, September 10, 2009

" 
rm -rf tmp/ : recursively deletes the directory tmp, and all files in it, including subdirectories. BE VERY CAREFULL WITH THIS COMMAND!!! 
" 
 
about 5 mins too late for the " BE VERY CAREFULL WITH THIS COMMAND!!! " 
 
i should just rip the " * " key from my leyboard
NeedHelpFast:) 09:29, September 23, 2009

As a total noob that has been left in the lurch by someone who called himself brilliant I'm desperate to learn how to stop being fiightened by my server and the commands - I'm a user really, so its all a worry to me. 
 
The server has several sites + ecommerce sites to care for!! 
 
Who would you employ (what kind of person/consultant) as a good / honest all round person that can basically site with me and take the mystery out of all this. 
 
Thanks for your help & advice :)
subash chandra 12:44, September 29, 2009

thanks for the infos.
ferdz 20:09, October 5, 2009

Can someone tell me how to upload a folder and a file using ssh? Or please tell me the command.
duduzile mthi 11:20, October 22, 2009

i will like to know more about cups(printer)
SP 08:04, November 19, 2009

Hi, 
If i want to copy the text from any file and paste the text in any file what i have to do for that ? 
 
2. I want to download file from server to my PC how can i do that ? i am using putty ..
shahz 18:57, December 5, 2009

Should include wget too :)
badtz 10:38, January 29, 2010

These are not SSH commands they are CLI commands via SSH. Other than that locate and find would be 2 moer good basic commands to add, knowing how to use find can save lots of time and trouble for beginners until they get used to *nix file organization.
George 14:35, April 20, 2010

Hello guys ! Which one is the command where i can find out the ip of the shell ?
mgehling 02:20, April 29, 2010

The IP to access shell should be the default ip. You will need to down a SSH client such as putty. You can find out the ip by asking your hosting provider for the ip address and finding out the port number. The default port number is 22.

ITIS
Shiv Narayan Bharawa 12:07, April 29, 2010

very good. Easy and understandable

Thanks.
subi 08:46, June 11, 2010

good
Guzzy 13:30, June 22, 2010

What is the command to list all the users that are currently logged in more than once?
Tendollz 05:41, July 6, 2010

Hello
How can i upload a folder on a shell and how can i give full permission to a shell so that it will be writable, readable and executable.
Filter 07:50, July 21, 2010

dd bs=1M if=/dev/sda | gzip | ssh user@remote 'dd of=sda.gz' Backup harddisk to remote machine
Greg Kerstin 00:18, September 1, 2010

How Do I split into parts. I would like 499 mb zip file parts from SSH command line
pi 22:02, September 2, 2010

:( i came here looking for ssh commands not bash commands

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