chmod [man page] - change file access permissions
chmod [OPTION]... MODE[,MODE]... FILE...
chmod [OPTION]... OCTAL-MODE FILE...
chmod [OPTION]... --reference=RFILE FILE...
change files and directories recursively
like verbose but report only when a change is made
output a diagnostic for every file processed
$ ls -ld dir/
Let's see how we can change file.txt permissions to rwxr-xr-- with octal mode:
$ chmod 764 file.txt
Symbolic specification is just another way to change file and directory permissions. In the next example we will change file.txt's permissions to rwxr-xr-- with a following symbolic specification:
$ chmod u=rwx,g=rx,o=r file.txt