Linux: file manipulation

Creating a file

We can use the command touch to create an empty file:

username@bash:~$ touch empty_file 
username@bash:~$ ls   
empty_file linux_tutorial 

Do not worry: later on in this tutorial you will learn how to put data into the files you have created.

Copying a file

There are several reasons why you may want to copy a file, for instance when you want to create a backup before modifying the original copy. The command to create copies is cp. It takes two arguments: the first one is the file to be copied (i.e. the source) and the second is the destination.

The destination is a path to either a file or a directory. If destination is a directory, then the cp command will create a copy of the source file in the destination directory and keep the original filename of the source file:

username@bash:~$ cp empty_file linux_tutorial 
username@bash:~$ ls linux_tutorial  
empty_file linux_tutorial_subdirectory

However, if the destination is a file, the cp command will create a copy of the source file with the new filename specified. This will be necessary when you want the copied file to have a different name:

username@bash:~$ cp empty_file linux_tutorial/empty_file_backup 
username@bash:~$ ls linux_tutorial  
empty_file empty_file_backup linux_tutorial_subdirectory

Copying a directory

We will use the same cp command to copy an entire directory, however now we need to specify the -r option, which will indicate we want to copy the directory and all of its files and subdirectories:

username@bash:~$ cp -r linux_tutorial linux_tutorial_backup 
username@bash:~$ ls   
empty_file linux_tutorial linux_tutorial_backup 
username@bash:~$ ls linux_tutorial_backup  
empty_file empty_file_backup linux_tutorial_subdirectory

Moving files and directories

The command to move a file or directory from one directory to another is mv (which stands for Move).mv works in similar way as cp, where the first argument is the source and the second one is the destination. One advantage of mv over cp is that mv do not need the option -r to move directories, so the command is actually the same either you want to move a file or a directory:

username@bash:~$ mkdir empty_directory
username@bash:~$ mv linux_tutorial/empty_file empty_directory
username@bash:~$ ls empty_directory 
empty_file 
username@bash:~$ ls linux_tutorial  
empty_file_backup linux_tutorial_subdirectory

So in the command above we’ve first created a new directory called empty_directory. Then, we have moved the file empty_file from the linux_tutorial to empty_directory.

Renaming files and directories

The command mv can also be used to rename a file or directory. This is accomplished when the source and destination directories are the same:

username@bash:~$ ls linux_tutorial
empty_file_backup linux_tutorial_subdirectory 
username@bash:~$ mv linux_tutorial/empty_file_backup linux_tutorial/empty_file_backup_renamed 
username@bash:~$ ls linux_tutorial  
empty_file_backup_renamed linux_tutorial_subdirectory

username@bash:~$ ls  
empty_directory  empty_file  linux_tutorial  linux_tutorial_backup
username@bash:~$ mv empty_directory empty_directory_renamed 
username@bash:~$ ls  
empty_directory_renamed empty_file linux_tutorial linux_tutorial_backup

In the first example, the file empty_file_backup, inside the directory linux_tutorial, was renamed to empty_file_backup_renamed.
In the second example, the directory empty_directory was renamed to empty_directory_renamed.

Removing a file

The command to remove a file is rm, which stands for Remove. The only argument it takes is the path to the file to be removed:

username@bash:~$ ls linux_tutorial_backup  
empty_file empty_file_backup linux_tutorial_subdirectory 
username@bash:~$ rm linux_tutorial/empty_file_backup  
username@bash:~$ ls linux_tutorial_backup  
empty_file linux_tutorial_subdirectory

Removing a directory

The command rm can also be used to remove entire directories, however just like for the command cp, we need to add the -r option:

username@bash:~$ ls  
empty_directory_renamed empty_file linux_tutorial linux_tutorial_backup
username@bash:~$ rm -r linux_tutorial_backup 
username@bash:~$ ls  
empty_directory_renamed empty_file linux_tutorial

Attention

Since Linux command line does not have an undo option, be careful when performing destructive actions.