How to Change File Permissions

1. List the file permissions.

   # ls -l filename

   -l	Displays the long listing, which includes current permissions for the file.
   filename	Is the specified file or directory.

2. Change the file permissions.

   # chmod nnn filename

   nnn	Are numbers representing the permissions you are assigning to the file owner, the group owner, and all others, in that order.
   filename	Is the specified file or directory.

   Permissions are changed using the numbers you specify.

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   Note -

   You can change permissions on groups of files or on all files in a directory using meta characters such as (*) in place of file names or in combination with them.

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3. Verify that the permissions have been changed by using the ls -l command.

   $ ls -l filename

   The long listing shows the current permissions for the file.

Example--Changing File Permissions

This example shows changing the permissions of a public directory from 744 (read/write/execute, read-only, and read-only) to 755 (read/write/execute, read/execute, and read/execute).

$ ls -ld public_dir
drwxr--r--  1 ignatz   staff    6023 Aug  5 12:06 public_dir
$ chmod 755 public_dir
$ ls -ld public_dir
drwxr-xr-x  1 ignatz   staff    6023 Aug  5 12:06 public_dir

This example show changing the permissions of an executable shell script from read/write to read/write/execute.

$ ls -l my_script
-rw------- 1 ignatz   staff    6023 Aug  5 12:06 my_script
$ chmod 700 my_script
$ ls -l my_script
-rwx------ 1 ignatz   staff    6023 Aug  5 12:06 my_script