Bash - 05 - Listing Files

The ls command is used to list files and directories in the current directory.

ls ~/Desktop/trial
# Using absolute path

ls /Users/sujith/Desktop/trial
# Another way using absolute path

ls -F Desktop
# List contents of Desktop directory

These commands display the contents of the Desktop directory (or any specified directory). The -F option appends a character to each file to indicate its type (e.g., / for directories, * for executables).

’ls’ with Multiple Directories

sujith@sujith-Latitude-7490:~$ ls ./ Desktop/ Documents/ Downloads/

In this example, the ls command lists the contents of multiple directories. However, using semicolons ; between the commands might not work as intended because semicolons separate commands rather than options.

sujith@sujith-Latitude-7490:~$ ls .; Desktop/; Documents/; Downloads/;

Desktop    Downloads  Music     Public  snap       Videos
Documents  grep.txt   Pictures  repos   Templates
bash: Desktop/: Is a directory
bash: Documents/: Is a directory
bash: Downloads/: Is a directory

The ls command should be executed separately for each directory or with valid options that do not cause errors.

Long Listing Format

-l option to get a more detailed view of files and directories:

sujith@sujith-Latitude-7490:~/Desktop$ ls -l

total 24
drwxrwxr-x 4 sujith sujith 4096 Sep  3 15:29  courses
drwxr-xr-x 2 sujith sujith 4096 Dec 22 16:11 'MCA Sem1 Books'
drwxr-xr-x 4 sujith sujith 4096 Dec 18 19:56  obsidian-vaults
drwxrwxr-x 7 sujith sujith 4096 Oct  6 15:21  Opage
drwxrwxr-x 6 sujith sujith 4096 Dec 24 10:09  pylab
drwxrwxr-x 8 sujith sujith 4096 Oct 26 09:04  websites
-rw-rw-r--  1 sujith sujith   68146 Dec 24 12:43  sujith.jpeg
-rw-rw-r--  1 sujith sujith 2957628 Oct 30 13:52 'Option WorkSheet.pdf'

Understanding the Output of ’ls -l'

1. File Type: The first part of file permissions. d represents a directory - represents a regular file l represents a symbolic link

2. Permissions (Mode): Shows the file’s access permissions for the owner, group, and others. rw- r-- --- 9 characters combined with file type becomes 10 characters. (. at end of permissions to indicate the SELinux content)

3. Hard Links: The number of hard links pointing to the file. For files, it is usually 1, and for directories, it is typically 2 but can be more.

4. User, Group: The user who owns the file and the group to which it belongs. For most users the group is the user’s private group. sujith sujith

5. Size: The size of the file or directory in bytes. 68146 for the sujith.jpeg file.

6. Last Modified Date: The last modification date and time of the file or directory. (creation date/time if not modified)

7. Name: The name of the file or directory. (For a symbolic link, the name is followed by -> )

Useful Options for ls

Options combined with ls to modify its output:

-a Show hidden files (those starting with .) and the . (current directory) and .. (parent directory).
-A Similar to -a but excludes . and ..

-g Similar to -l but the owner is not shown.
-G Group owner is hidden (along with -l)

-h Displays file sizes in human readable format (KB, MB) (along with -l).
-i Shows inode numbers for the files

-r Reverse alphabetical order of file listing.
-R Recursive listing (listing all contents of all sub directories)

-s Size shown in blocks instead of bytes (along with -l).
-S Sort files by size (used with -l)

-t Sorts files by modification time (along with -l).
-X Extension based sorting (along with -l)

-C Displays the output in columns (default behavior).
-1 Displays 1 file per line (not to use columns)

These options an be combined in any order:

ls -Fal    # Combined options (file types, human-readable sizes, and long listing)
ls -la     # Long listing with hidden files
ls -al     # Another variation