SSH Cheat Sheet This page designed to help beginners starting out with SSH by providing a united snakesble "SSH cheat sheet" full of common commands. Delete an entire directory and all of its contents:
rm -r -f YourDirectory What's happening: rm = remove / delete -r = recursively deletes the directory and all files in it, including subdirectories -f = will not ask for confirmation before deleting Extract a TAR.GZ File
tar -xvf yourfilename.tar.gz What's happening: tar – is calling the tar program -x – extract -z – it's gzipped (so omit the z if you merely have a .tar file) -f – supplying filename on command line. Move a directory and/or files to another location on the server:
mv directory/* html/ What's happening: mv – move directory/* – All files/folders inside the Directory folder html/ – Location of where the files will be moved to
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 | 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 |
How do I unzip a file with telnet? All of the below commands assume that you are within the same directory that the compressed file is in. To be sure type:
ls {enter} If the file is there, you're ready to go. If not type:
cd /big/dom/xdomain/www/directory/ {enter} replacing the path with the correct path to your file. If a file ends in .zip (for example, file.zip) type:
unzip file.zip If a file ends in .tar (e.g., file.tar) type:
tar -xvf file.tar If a file ends in .gz (for example, file.gz) type:
gzip -d file.gz If a file ends in .tar.gz (e.g. file.tar.gz) type:
gzip -d file.tar.gz and then
tar -xvf file.tar If a file ends in .tgz (e.g. file.tgz)
| zip [options] [zipfile] [files] | The zip command compresses a file or list of files into a zip format archive file. This command is compatible with pkzip on a PC. Simply type "zip zipfile file1 file2 file3″ at a telnet command prompt and replace zipfile with the name you want to use for your compressed zip archive file, and replace fileX with the name of the file(s) you want to compress into the zip archive.
| For example, type "zip backup.zip home.html index.html" at a telnet command prompt to compress and archive the files called home.html and index.html into the file called backup.zip.
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| | unzip [options] [zipfile] | The unzip command extracts a zip format archive file. This command is compatible with pkunzip files from a PC. Simply type "unzip zipfile" at a telnet command prompt and replace zipfile with the name of your zip format archive file.
| For example, type "unzip -aL old.zip" at a telnet command prompt to extract files contained in the archive called old.zip. The "-aL" are options that are generally useful when unzipping files created on a PC.
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Moving files via SSH Often you will need to move one or more files/folders or copy them to a different location. You can do so easily using an SSH connection. The commands which you would need to use are
mv (short for 'move') and
cp (short for 'copy').
The mv command syntax looks like this:
mv configuration.php-dist configuration.php[/code] By issuing the above command we will move (rename) the file configuration.php-dist to configuration.php.
You can also use mv to move a whole directory and its content:
mv includes/* ./[/code] This will move all files (and folders) in the includes/ directory to the current working directory.
In some cases however, we will need to only update the files and move only files that were changed, which we can do by passing '-u' as argument to the command:
mv -u includes/* admin/includes[/code] The copy (
cp) command works the same way as
mv, but instead of moving the files/folders it copies them. For example:
cp configuration.php-dist configuration.php[/code] The command will copy the
configuration.php-dist file to
configuration.php and will preserve the original file (the file will NOT be removed after it is copied).
cp also accepts various arguments:
cp -R includes/ includes_backup/[/code]
-R instructs
cp to copy files recursively (for example, a whole directory). To overwrite already existing files you should use the
-f argument:
cp -Rf includes/ admin/includes/[/code]
To find all GB files for instance I would use du and grep, though the other methods mentioned here seem great as well.
[code]du -h -a /dir | grep "[0-9]Gb"
[/code]
You can also get fancy with the --except option that du has.