Files and directories (another name for folders) are at the heart of Linux, so being able to create, view, move, and delete them from the command line is very important and quite powerful. These file manipulation commands allow you to perform the same tasks that a graphical file explorer would perform.
Create an empty text file called myFile:
Rename myFile to myFirstFile:
mv myFile myFirstFile
View the contents of a file:
cat myFirstFileView the content of a file with pager (one screenful at a time):
View the content of a file with pager (one screenful at a time):
View the first several lines of a file:
View the last several lines of a file:
Edit a file:
See what files are in your current working directory:
Create an empty directory called myFirstDirectory:
Create multi path directory: (creates two directories, src and myFirstDirectory)
mkdir -p src/myFirstDirectory
Move the file into the directory:
mv myFirstFile myFirstDirectory/
You can also rename the file:
user@linux-computer:~$ mv myFirstFile secondFileName
Change the current working directory to myFirstDirectory:
Delete a file:
Move into the parent directory (which is represented as ..):
Delete an empty directory:
Delete a non-empty directory (i.e. contains files and/or other directories):
rm -rf myFirstDirectory
Make note that when deleting directories, that you delete ./ not / that will wipe your whole filesystem.
The ls command has several options that can be used together to show more information.
The l option shows the file permissions, size, and last modified date. So if the root directory contained a dir called test and a file someFile the command:
user@linux-computer:~$ ls -l
Would output something like
-rw-r--r-- 1 user users 70 Jul 22 13:36 someFile.txt drwxrwxrwx 2 user users 4096 Jul 21 07:18 test
The permissions are in the format of drwxrwxrwx. The first character represents the file type d if it’s a directory – otherwise. The next three rwx are the permissions the user has over the file, the next three are the permissions the group has over the file, and the last three are the permissions everyone else has over the file.
The r of rwx stands for if a file can be read, the w represents if the file can be modified, and the x stands for if the file can be executed. If any permission isn’t granted a – will be in place of r, w, or x.
So from above user can read and modify someFile.txt but the group has only read-only rights.
To change rights you can use the chmod ### fileName command if you have sudo rights. r is represented by a value of 4, w is represented by 2, and x is represented by a 1. So if only you want to be able to modify the contents
to the test directory.
Owner rwx = 4+2+1 = 7 Group r-x = 4+0+1 = 5 Other r-x = 4+0+1 = 5
So the whole command is
chmod 755 test
Now doing a ls -l would show something like
drwxr-xr-x 2 user users 4096 Jul 21 07:20 test
Used in conjunction with the l option the h option shows file sizes that are human readable. Running
user@linux-computer:~$ ls -lh
total 4166 -rw-r--r-- 1 user users 70 Jul 22 13:36 someFile.txt drwxrwxrwx 2 user users 4.0K Jul 21 07:18 test
To view hidden files use the a option. For example
user@linux-computer:~$ ls -a
.profile someFile.txt test
Total Directory Size
To view the size of the current directory use the s option (the h option can also be used to make the size more readable).
user@linux-computer:~$ ls -s
Outputs total 4166 someFile.txt test
Lets say test directory had a file anotherFile and you wanted to see it from the root folder, you could use the R option which would list the recursive tree.
user@linux-computer:~$ ls -R
Outputs .: someFile.txt test ./test: anotherFile