Difference between revisions of "Top Chmod Command Examples for Beginners"

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Latest revision as of 17:51, 5 May 2018

Top Chmod Command Examples for Beginners

Let us review how to use symbolic representation with chmod.

Following are the symbolic representation of three different roles:

u is for user, g is for group, and o is for others. Following are the symbolic representation of three different permissions:

r is for read permission, w is for write permission, x is for execute permission. Following are few examples on how to use the symbolic representation on chmod.

Add single permission to a file/directory

Changing permission to a single set. + symbol means adding permission. For example, do the following to give execute permission for the user irrespective of anything else:

$ chmod u+x filename

Add multiple permission to a file/directory

Use comma to separate the multiple permission sets as shown below.

$ chmod u+r,g+x filename

Remove permission from a file/directory

Following example removes read and write permission for the user.

$ chmod u-rx filename

Change permission for all roles on a file/directory

Following example assigns execute privilege to user, group and others (basically anybody can execute this file).

$ chmod a+x filename

Make permission for a file same as another file (using reference)

If you want to change a file permission same as another file, use the reference option as shown below. In this example, file2’s permission will be set exactly same as file1’s permission.

$ chmod --reference=file1 file2

Apply the permission to all the files under a directory recursively

Use option -R to change the permission recursively as shown below.

$ chmod -R 755 directory-name/

Change execute permission only on the directories (files are not affected)

On a particular directory if you have multiple sub-directories and files, the following command will assign execute permission only to all the sub-directories in the current directory (not the files in the current directory).

$ chmod u+X *

Note: If the files has execute permission already for either the group or others, the above command will assign the execute permission to the user