Directories and Navigation
Source repo: basic_skills | Branch:
hpc-training-doc| Last synced: 2026-04-24 10:27:17.425 UTC
Directories and the current location
In unix, everything is a file, which can be confusing at first. The locations for where files are stored are called directories (which is equivalent to folders), and are also viewed as files by the operating system. To find out where you are in the system, use the pwd command (print working directory), which prints the full path to the directory you are currently in:
[username@login02 ~]$ pwd
/home/username
Listing directory contents
To see what are the contents of the current directory are, use the file listing command ls:
[username@login02 ~]$ ls
filelisting.txt intel loadgccomgnuenv.sh loadgnuenv.sh loadintelenv.sh tools
In every Unix directory, there are "hidden" files (just like on Macs and Windows machines), to see them, run the ls -a command:
[username@login02 ~]$ ls -a
. .bash_history .bashrc .gitconfig loadgccomgnuenv.sh .ncviewrc .ssh .vimrc
.. .bash_logout .config filelisting.txt intel loadgnuenv.sh .petscconfig tools .Xauthority
.alias .bash_profile .kshrc loadintelenv.sh .slurm .viminfo
File details and permissions
In Unix, sometimes it is hard tell if a file is a directory. To see file details (including timestamp and size), run the ls -l command:
[username@login02 ~]$ ls -l
-rw-r--r-- 1 username abc123 322 Jul 17 21:04 filelisting.txt
drwxr-xr-x 3 username abc123 3 Jun 22 2023 intel
-rwx------ 1 username abc123 101 Jun 27 2023 loadgccomgnuenv.sh
-rwx------ 1 username abc123 77 Oct 16 2023 loadgnuenv.sh
-rwxr-xr-x 1 username abc123 125 Oct 16 2023 loadintelenv.sh
drwxr-xr-x 2 username abc123 4 Jun 30 2023 tools
You can combine the two commands above and use it to see the full directory and file information:
[username@login02 ~]$ ls -al
total 166
drwx------ 7 username abc123 23 Jul 17 19:33 .
drwxr-xr-x 143 root root 0 Jul 17 20:01 ..
-rw-r--r-- 1 username abc123 2487 Jun 23 2023 .alias
-rw------- 1 username abc123 14247 Jul 17 12:11 .bash_history
-rw-r--r-- 1 username abc123 18 Jun 19 2023 .bash_logout
-rw-r--r-- 1 username abc123 176 Jun 19 2023 .bash_profile
-rw-r--r-- 1 username abc123 159 Jul 17 18:24 .bashrc
drwx------ 3 username abc123 3 Oct 23 2023 .config
-rw-r--r-- 1 username abc123 322 Jul 17 21:04 filelisting.txt
-rw-r--r-- 1 username abc123 1641 Jun 22 2023 .gccomrc
-rw-r--r-- 1 username abc123 245 Jun 28 2023 .gitconfig
drwxr-xr-x 3 username abc123 3 Jun 22 2023 intel
-rw-r--r-- 1 username abc123 171 Jun 19 2023 .kshrc
-rwx------ 1 username abc123 101 Jun 27 2023 loadgccomgnuenv.sh
-rwx------ 1 username abc123 77 Oct 16 2023 loadgnuenv.sh
-rwxr-xr-x 1 username abc123 125 Oct 16 2023 loadintelenv.sh
[snip extra lines]
There are several things to notice in the above listing: the first column of data is information about the file "permissions", which controls who can see/read/modify what files (r=read, w=write, x=execute, -=no permission); the next 2 columns are the username and groupID; the 3rd and 4th columns are the size and date. This is discussed in more detail in the Permissions section below. Also, note that two files have dots for their names: in unix the "dot" is a component of a filename. When working with filenames, a leading dot is the prefix of a "hidden" file, a file that an ls will not normally show. But also, the single dot, . represents the current working directory, and the double dots, .. represent the directory above. You use these as arguments to unix commands dealing with directories.
Creating and navigating directories
There are simple Linux commands to create and remove directories, and to populate the directories.
To create a directory, use the mkdir, make directory command (more about directories in the sections below):
[username@login02 ~]$ mkdir testdir
[username@login02 ~]$ ls -l
total 12
drwxr-xr-x 3 username abc123 3 Jun 22 2023 intel
-rwx------ 1 username abc123 101 Jun 27 2023 loadgccomgnuenv.sh
-rwx------ 1 username abc123 77 Oct 16 2023 loadgnuenv.sh
-rwxr-xr-x 1 username abc123 125 Oct 16 2023 loadintelenv.sh
drwxr-xr-x 2 username abc123 2 Jul 17 20:49 testdir
drwxr-xr-x 2 username abc123 4 Jun 30 2023 tools
To move into that directory, use the cd, change directory command:
[username@login02 ~]$ cd testdir/
[username@login02 testdir]$ ls -al
total 20
drwxr-xr-x 2 username abc123 2 Jul 17 20:49 .
drwxr-x--- 9 username abc123 25 Jul 17 20:49 ..
[username@login02 testdir]$
From this directory, you can use the .. command to see the contents of the directory above:
[username@login02 testdir]$ ls -l ..
[username@login02 testdir]$ /bin/ls -l ..
total 22
drwxr-xr-x 4 username abc123 5 Jul 17 20:43 expanse-examples
-rw-r--r-- 1 username abc123 322 Jul 17 21:04 filelisting.txt
drwxr-xr-x 3 username abc123 3 Jun 22 2023 intel
-rwx------ 1 username abc123 101 Jun 27 2023 loadgccomgnuenv.sh
-rwx------ 1 username abc123 77 Oct 16 2023 loadgnuenv.sh
-rwxr-xr-x 1 username abc123 125 Oct 16 2023 loadintelenv.sh
drwxr-xr-x 2 username abc123 4 Jul 17 20:53 testdir
drwxr-xr-x 2 username abc123 4 Jun 30 2023 tools
Removing files and directories
To remove files and directories there are different mechanisms, depending on whether or not the directory is empty or contains files.
[username@login01 testdir]$ cd ..
[username@login01 testdir]$ mkdir testdir2
[username@login01 testdir]$ cd testdir2
[username@login01 testdir2]$ mkdir dir1
[username@login01 testdir2]$ mkdir dir2
[username@login01 testdir2]$ mkdir dir3
Next, create some testfiles using the touch command:
[username@login01 testdir2]$ touch f1
[username@login01 testdir2]$ touch f2
[username@login01 testdir2]$ touch f3
[username@login01 testdir2]$ touch dir2/file1
[username@login01 testdir2]$ touch dir2/file2
[username@login01 testdir2]$ touch dir2/file3
For a file, we use the remove, rm command:
[username@login01 testdir2]$ rm f3
For an empty directory, we can use the rmdir command:
[username@login01 testdir2]$ rmdir dir1
If the directory has contents (files or subdirectories), you use the rm command with arguments to force the removal of the directory and all of its contents.
[username@login01 testdir2]$ rm -rf dir3