A Quick Summary of Unix Commands

ls - List information about files.

ls -l -c -r

-l Show all file details
-t Sort by modification time
-r Reverse
-a include hidden files -c Use time of last modification of the i-node

Directory Abbreviations

You can use directory abbreviations to shorten the pathnames of a complex directory structure. The following list shows some useful abbreviations:

~ Your home directory
.. Parent directory-the directory just above your current directory
. Current directory

count files in a directory

ls -l | wc -l
ls -la | wc -l    (To include hidden files)

count files in a directory recursively

find . -type f | wc -l

count subdirectories in a directory recursively

find . -type d | wc -l

Recursively change the owner of all files in a directory

chown -R webmaster html

Recursively change the owner and group of all files in a directory

chown -R webmaster:webgroup html

Recursively change files to rwx for owner and r for the rest.

find . -type f -exec chmod u=rwx,go=r {} \;
find . -type d -exec chmod u=rwx,go=rx {} \;

Recursively delete files with given pattern.

find . -name '*.pdb' -exec rm {} \;

Locate a binary, source, and manual page files for a command.

whereis filename