What is the mv command in UNIX?

The mv command is a command line utility that moves files or directories from one place to another . It supports moving single files, multiple files and directories. It can prompt before overwriting and has an option to only move files that are new than the destination.

How to move a file

To move a file using the mv command pass the name of the file and then the new name for the file. In the following example the file foo.txt is renamed to bar.txt.

ls
foo.txt
mv foo.txt bar.txt
ls 
bar.txt

How to move a file into a directory

To move a file into a directory using the mv command pass the name of the file and then the directory. In the following example the file foo.txt is moved into the directory bar.

tree -F .
.
├── bar/
└── foo.txt
mv foo.txt bar
tree -F 
.
└── bar/
    └── foo.txt

How to move multiple files into a directory

To move multiple files using the mv command pass the names of the files or a pattern followed by the destination.

mv file1.txt file.2.txt file3.txt folder

The following example is the same as above but uses pattern matching to move all files with a .txt extension.

mv *.txt folder

How to move a directory

To move a directory using the mv command pass the name of the directory to move followed by the destination.

ls -F 
foo/
mv foo bar
ls -F
bar/

How to prompt before overwriting a file

By default the mv command will overwrite an existing file. Consider the following example.

ls 
foo.txt bar.txt
mv foo.txt bar.txt
ls
bar.txt

In this example bar.txt is overwritten by the file file.txt. At some point when running mv a file that was not meant to be overwritten probably will be. To prompt before overwriting a file the -i option can be used.

ls 
foo.txt bar.txt
mv -i foo.txt bar.txt
mv: overwrite 'bar.txt'? n

How to not overwrite an existing file

To prevent an existing file from being overwritten pass the -n option. This causes the mv command to ignore anything that would overwrite an existing file. In the following example the effect is for nothing to happen as a file would be overwritten.

ls 
foo.txt bar.txt
mv -n foo.txt bar.txt
ls
foo.txt bar.txt

How to only move files newer than the destination

To only move files that are newer than the destination pass the -u option. If a file is not newer than a file with the same name in the destination it will not be moved.

tree -F .
.
├── foo/
│   ├── bar.txt
│   └── foo.txt
├── bar.txt
└── foo.txt

Looking at the timestamps of these files we can see that the file foo.txt in the current directory is newer than the file foo.txt in the directory bar.

ls -l
total 4
drwxr-xr-x 2 george users 4096 Oct 11 20:18 bar
-rw-r--r-- 1 george users    0 Oct 11 20:18 bar.txt
-rw-r--r-- 1 george users    0 Oct 11 20:20 foo.txt
ls -l bar
total 0
-rw-r--r-- 1 george users 0 Oct 11 20:18 bar.txt
-rw-r--r-- 1 george users 0 Oct 11 20:23 foo.txt

Using the -u option means that only newer files will be moved.

mv foo.txt bar.txt bar
ls 
bar foo.txt

The file foo.txt is not moved as it is older than the file in the destination folder.

How to take a backup of an existing file

To take a backup of an existing file that will be overwritten as a result of the mv command pass the -b option. This will create a backup file with the tilde character appended to it.

ls 
foo.txt bar.txt
mv -b foo.txt bar.txt
ls
bar.txt  bar.txt~

To change the backup suffix the -S option may be used.

ls 
foo.txt bar.txt
mv -S .bak -b foo.txt bar.txt
ls
bar.txt  bar.txt.bak

Further reading

• mv man page
• mv Wikipedia page
• The mv command
• mv (rename) files