Common SSH Commands - Linux Shell Commands

 

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


 

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)

 

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