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tutorials:unix_commands [2016/03/27 21:07]
Richard.Randriatoamanana@ec-nantes.fr created
tutorials:unix_commands [2016/03/27 21:27]
Richard.Randriatoamanana@ec-nantes.fr
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 ====Common Linux Shell Commands==== ====Common Linux Shell Commands====
-**ls** : list files/​directories in a directory, comparable to dir in windows/​dos. +===ls=== 
-<code bash>ls -al</​code>​ +List files/​directories in a directory, comparable to dir in windows/​dos. 
-shows all files (including ones that start with a period), directories,​ and details attributes for each file. +<code bash>ls -al 
 +#shows all files (including ones that start with a period), directories,​ and details attributes for each file.</​code>​
  
-cd : change ​directory ·· cd /​usr/​local/​apache : go to /​usr/​local/​apache/​ directory  +===cd===  
-cd ~ go to your home directory  +Change ​directory ·· cd /​usr/​local/​apache : go to /​usr/​local/​apache/​ directory ​ 
-cd - go to the last directory you were in +<code bash> 
-cd .. go up a directory cat : print file contents to the screen ​+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</​code>​
  
-cat filename.txt : cat the contents of filename.txt to your screen ​ +===chmod=== 
- +Changes ​file access permissions
-chmod: changes ​file access permissions +
-The set of 3 go in this order from left to right: +
-USER - GROUP - EVERONE+
  
 +The set of 3 go in this order from left to right: **USER - GROUP - EVERYONE** <code bash>
 0 = --- No permission 0 = --- No permission
-1 = --Execute only +1 = --Execute only 
-2 = -W- Write only +2 = -w- Write only 
-3 = -WX Write and execute +3 = -wx Write and execute 
-4 = R-- Read only +4 = r-- Read only 
-5 = R-Read and execute +5 = r-Read and execute 
-6 = RW- Read and write +6 = rw- Read and write 
-7 = RWX Read, write and execute +7 = rwx Read, write and execute</​code>​
- +
-Usage:  +
-chmod numberpermissions filename +
- +
-chmod 000 : No one can access  +
-chmod 644: Usually for HTML pages +
-chmod 755: Usually for CGI scripts +
  
-chownchanges file ownership permissions +Usage''​chmod numberpermissions filename/​directory''<​code bash> 
-The set of 2 go in this order from left to right: +chmod 000  #No one can access  
-USER - GROUP+chmod 644  #Usually for HTML pages 
 +chmod 755  #Usually for CGI scripts</​code>​
  
-chown root myfile.txt : Changes the owner of the file to root +===chown===  
-chown root.root myfile.txt : Changes ​the owner and group of the file to root+Changes file ownership permissions
  
 +The set of 2 go in this order from left to right: **USER - GROUP**<​code bash>
 +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</​code>​
  
-tail : like cat, but only reads the end of the file +===tail=== 
-tail /​var/​log/​messages ​see the last 20 (by default) lines of /​var/​log/​messages  +Like ''​cat''​, but only reads the end of the file.<code bash> 
-tail -f /​var/​log/​messages ​watch the file continuously,​ while it's being updated  +tail /​var/​log/​messages ​     # ​see the last 20 (by default) lines of /​var/​log/​messages  
-tail -200 /​var/​log/​messages ​print the last 200 lines of the file to the screen+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</​code>​
  
-more like cat, but opens the file one screen at a time rather than all at once  +===more/less=== 
-more /​etc/​userdomains ​browse through the userdomains file. hit Space to go to the next page, q to quit +like cat, but opens the file one screen at a time rather than all at once<code bash> 
 +more /​etc/​userdomains ​browse through the userdomains file. hit Space to go to the next page, q to quit</​code>​
  
-pico : friendly, easy to use file editor ​ +===vi=== 
-pico /​home/​burst/​public_html/​index.html ​edit the index page for the user's website+<code bash>​vi ​/​home/​burst/​public_html/​index.html ​edit the index page for the user's website</​code>​
  
-File Editing with VI commands +While in the vi program you can use the following useful commands, you will need to hit SHIFT + : to go into command mode<code bash> 
-vi : another editor, tons of features, harder to use at first than pico  +:q! # This force quits the file without saving and exits vi 
-vi /​home/​burst/​public_html/​index.html : edit the index page for the user's website.  +:w  # This writes the file to disk, saves it 
-Whie in the vi program you can use the following useful commands, you will need to hit SHIFT + : to go into command mode+: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</​code>​
  
-:q! : This force quits the file without saving and exits vi +  * [[http://​www.tutorialspoint.com/​unix/​unix-vi-editor.htm]] 
-:w : This writes the file to disk, saves it +  * [[http://​www.openvim.com|interactive tutorial]]
-: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=== 
-grep root /​etc/​passwd ​shows all matches of root in /​etc/​passwd +Looks for patterns in files <code bash> 
-grep -v root /​etc/​passwd ​shows all lines that do not match root +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</​code>​
  
-ln : create's "​links"​ between files and directories +===ln===  
-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. ​+Create's "​links"​ between files and directories<code bash> 
 +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 original, however you can delete the link and it will not delete the original.</​code>​
  
-last : shows who logged in and when +===last=== 
-last -20 shows only the last 20 logins  +Shows who logged in and when<code bas> 
-last -20 -a shows last 20 logins, with the hostname in the last field +last -20    # ​shows only the last 20 logins  
 +last -20 -a shows last 20 logins, with the hostname in the last field </​code>​
  
-shows who is currently logged in and where they are logged in from. +===w=== 
-who This also shows who is on the server in an shell.+shows who is currently logged in and where they are logged in from. 
 +<code bash>who This also shows who is on the server in an shell</​code>​
  
-netstat ​shows all current network connections. +===netstat=== 
-netstat -an shows all connections to the server, the source and destination ips and ports. +shows all current network connections. 
-netstat -rn shows routing table for all ips bound to the server.+<code bash> 
 +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.</​code>​
  
-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=== 
 +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 top then type Shift + M to sort by memory usage or Shift + P to sort by CPU usage
  
-psps is short for process status, which is similar to the top command. It's used to show currently running processes and their PID. +===ps=== 
-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// 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).<code bash> 
-ps U username ​shows processes for a certain user +ps U username ​shows processes for a certain user 
-ps aux shows all system processes +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!+ps aux --forest ​shows all system processes like the above but organizes in a hierarchy that's very useful!</​code>​
  
-touch : create ​an empty file  +===touch===  
-touch /​home/​burst/​public_html/​404.html ​create an empty file called 404.html in the directory /​home/​burst/​public_html/ ​+creates ​an empty file <code bash> 
 +touch /​home/​burst/​public_html/​404.html ​create an empty file called 404.html in the directory /​home/​burst/​public_html/ ​</​code>​
  
-file attempts to guess what type of file a file is by looking at it's content.  +===file=== 
-file * prints out a list of all files/​directories in a directory ​+attempts to guess what type of file a file is by looking at it's content.  
 +<code bash>file * prints out a list of all files/​directories in a directory</​code>​
  
-du shows disk usage.  +===du===  
-du -sh shows a summary, in human-readble form, of total disk space used in the current directory, including subdirectories. +shows disk usage.<code bash> 
-du -sh * same thing, but for each file and directory. helpful when finding large files taking up space. ​+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. ​</​code>​
  
-wc word count +===wc=== 
-wc -l filename.txt ​tells how many lines are in filename.txt ​+word count 
 +<code bash>wc -l filename.txt ​tells how many lines are in filename.txt</​code>​
  
-cp copy a file  +===cp===  
-cp filename filename.backup ​copies filename to filename.backup +copy a file <code bash> 
-cp -a /​home/​burst/​new_design/​* /​home/​burst/​public_html/ ​copies all files, retaining permissions form one directory to another.  +cp filename filename.backup ​copies filename to filename.backup 
-cp -av * ../​newdir ​Copies all files and directories recurrsively in the current directory INTO newdir+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</​code>​
  
-mv : Move a file command +===mv=== 
-mv oldfilename newfilename ​Move a file or directory from oldfilename to newfilename+move a file command<code bash> 
 +mv -v oldfilename newfilename ​Move a file or directory from oldfilename to newfilename ​in a verbose mode</​code>​
  
-rm delete a file +===rm===  
-rm filename.txt ​deletes filename.txt,​ will more than likely ask if you really want to delete it +delete a file 
-rm -filename.txt ​deletes filename.txt,​ will not ask for confirmation before deleting. +<code bash>rm -vi filename.txt ​deletes filename.txt,​ will more than likely ask if you really want to delete it 
-rm -rf tmp/ recursively deletes the directory tmp, and all files in it, including subdirectories. BE VERY CAREFULL WITH THIS COMMAND!!! ​+rm -fv filename.txt ​deletes filename.txt,​ will not ask for confirmation before deleting. 
 +rm -rfv tmp/ recursively deletes the directory tmp, and all files in it, including subdirectories. BE VERY CAREFULL WITH THIS COMMAND!!!</​code>​
  
-TAR: Creating ​and Extracting .tar.gz and .tar files +===tar===  
-tar -zxvf file.tar.gz ​Extracts the file +creating ​and Extracting .tar.gz and .tar files<code bash> 
-tar -xvf file.tar ​Extracts the file +tar -zxvf file.tar.gz ​        # Extracts the file that have been compressed 
-tar -cf archive.tar contents/ ​Takes everything from contents/ and puts it into archive.tar +tar -xvf file.tar ​            # Extracts the file 
-gzip -d filename.gz ​Decompress the file, extract it+tar -cf archive.tar contents/ ​Takes everything from contents/ and puts it into archive.tar 
 +gzip -d filename.gz ​          # Decompress the file, extract it</​code>​
tutorials/unix_commands.txt · Last modified: 2016/03/27 21:27 by Richard.Randriatoamanana@ec-nantes.fr