chmod command is used to set permission bit on file or directory. It also allows to clone/copy permissions of one file to another. For example we have two files with following permissions:
$ ls -l file* -rwxr-xr--. 1 lrendek lrendek 0 Apr 7 14:39 file1 -rw-rw-r--. 1 lrendek lrendek 0 Apr 7 14:40 file2
Both files have different permissions. Using --reference option the chmod command is capable to clone permissions from one file to another. For example the below command will clone permissions of file1 and use it as a reference to set permissions on file2:
$ chmod --reference=file1 file2
Permissions of the file2 file were cloned and set to be the same as permissions of file1 file.
$ ls -l file* -rwxr-xr--. 1 lrendek lrendek 0 Apr 7 14:39 file1 -rwxr-xr--. 1 lrendek lrendek 0 Apr 7 14:40 file2
The same syntax also applies for directories:
$ ls -ld dir* d--x--x--x. 2 lrendek lrendek 40 Apr 7 14:52 dir1 drwxrwxr-x. 2 lrendek lrendek 40 Apr 7 14:52 dir2 $ chmod --reference=dir1 dir2 $ ls -ld dir* d--x--x--x. 2 lrendek lrendek 40 Apr 7 14:52 dir1 d--x--x--x. 2 lrendek lrendek 40 Apr 7 14:52 dir2