UNIX Shell Commands

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The following is a list of UNIX commands that you might find helpful when modifying your web sites on the server. Most UNIX commands have many options and parameters which are not listed here. For more complete information on using UNIX commands, you can refer to the online manual by typing man [command] at the UNIX prompt, where "[command]" represents the command you would like more information about. Other UNIX help commands you can type are [command] -? and [command] --help.

Example: man ls
This would bring up the help documentation for the "LS" command.

Note: When something is specified in brackets, such as [command] or [filename], it is used to indicate that you must input your desired information here. Do NOT include brackets in your command.

Navigating in UNIX

pwd Shows the full path of the current directory
ls Lists all the files in the current directory
ls -al Lists all files and information
ls –alR Lists all files and information in all subdirectories
ls -alR | more Same as ls –alR, pausing when screen becomes full
ls -alR > filename.txt Same as ls –alR, outputs the results to a file
ls *.html Lists all files ending with .html
cd [directory name] Changes to a new directory
cd .. Changes to directory above current one
clear Clears the screen
vdir Gives a more detailed listing than the "ls" command
exit Log off your shell

Moving, Copying and Deleting Files

mv [old filename] [new filename] Move/rename a file
cp [filename] [new filename] Copies a file
rm [filename] Deletes a file
rm * Deletes all files in current directory
rm *.html Deletes all files ending in .html

Creating, Moving, Copying and Deleting Directories

mkdir [directory name] Creates a new directory
ls -d */ Lists all directories within current directory
cp -r [directory] [new directory] Copies a directory and all files/directories in it

Searching Files and Directories

find . -name [filename] -print Searches for a file starting with current directory
grep [text] [filename] Searches for text within a file

File and Directory Permissions

There are three levels of file permissions: read, write and execute.  In addition, there are three groups to which you can assign permissions: file owner, user group and everyone.  The command chmod followed by three numbers is used to change permissions.  The first number is the permission for the owner, the second for the group and the third for everyone.  Here are how the levels of permission translate:

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

It is preferred that the group always have permission of 0.  This prevents other users on the server from browsing files via Telnet and FTP.  Here are the most common file permissions used:

chmod 604 [filename] Minimum permissions for HTML file
chmod 705 [directory name] Minimum permissions for directories
chmod 755 [filename] Minimum permissions for scripts & programs
chmod 606 [filename] Permissions for data files used by scripts
chmod 703 [directory name] Write-only permissions for public FTP uploading

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