Read Filename in Folder in Shell Script
Since the creation of Unix in the 1970s, a lot of operating systems have used it as their foundation. Many of these operating systems failed, while others succeeded.
Linux is 1 of the near popular Unix based operating systems. It's open source, and is used all over the world beyond many industries.
I amazing feature of the Linux operating system is the Command Line Interface (CLI) which allows users to interact with their computer from a shell. The Linux shell is a REPL (Read, Eastwardvaluate, Print, Loop) environs where users tin can enter a command and the shell runs it and returns a result.
The ls command is i of the many Linux commands that allow a user to listing files or directories from the CLI.
In this article, we'll go in depth on the ls command and some of the most important flags you'll demand day-to-solar day.
Prerequisites
- A computer with directories and files
- Take ane of the Linux distros installed
- Basic knowledge of navigating effectually the CLI
- A smile on your face :)
The Linux ls Command
The ls command is used to list files or directories in Linux and other Unix-based operating systems.
Just like you navigate in your File explorer or Finder with a GUI, the ls control allows yous to list all files or directories in the current directory by default, and farther interact with them via the command line.
Launch your terminal and blazon ls to encounter this in action:
How to list Files in a Directory with Options
The ls command also accepts some flags (likewise known as options) which are additional information that changes how files or directories are listed in your concluding.
In other words, flags change how the ls command works:
ls [flags] [directory] PS: The word contents used in throughout the article refers to the files and directories existence listed, not the bodily contents of the files/directories ?
List files in the current working directory
Type the ls command to list the contents of the electric current working directory:
List files in another directory
Blazon the ls [directory path here] command to list the contents of some other directory:
List files in the root directory
Type the ls / command to list the contents of the root directory:
Listing files in the parent directory
Type the ls .. command to list the contents of the parent directory one level above. Utilise ls ../.. for contents two levels higher up:
List files in the user'southward home directory (/abode/user)
Type the ls ~ command to listing the contents in the users'southward home directory:
List merely directories
Type the ls -d */ command to listing only directories:
List files with subdirectories
Type the ls * command to list the contents of the directory with it'due south subdirectories:
Listing files recursively
Type the ls -R control to list all files and directories with their corresponding subdirectories downwards to the last file:
If you accept a lot of files, this can have a very long fourth dimension to complete as every single file in each directory volition be printed out. You tin instead specify a directory to run this command in, like so: ls Downloads -R List files with their sizes
Blazon the ls -s command (the s is lowercase) to list files or directories with their sizes:
Listing files in long format
Type the ls -50 command to list the contents of the directory in a tabular array format with columns including:
- content permissions
- number of links to the content
- owner of the content
- group owner of the content
- size of the content in bytes
- last modified date / time of the content
- file or directory name
List files in long format with readable file sizes
Type the ls -lh command to listing the files or directories in the same table format higher up, simply with another column representing the size of each file/directory:
Notation that sizes are listed in bytes (B), megabytes (MB), gigabytes (GB), or terabytes (TB) when the file or directory's size is larger than 1024 bytes.
List files including hidden files
Type the ls -a control to list files or directories including hidden files or directories. In Linux, anything that begins with a . is considered a hidden file:
List files in long format including hidden files
Type the ls -fifty -a or ls -a -50 or ls -la or ls -al control to list files or directories in a tabular array format with extra data including hidden files or directories:
Listing files and sort past date and fourth dimension
Type the ls -t command to list files or directories and sort by concluding modified date in descending order (biggest to smallest).
You tin can also add together a -r flag to reverse the sorting order similar so: ls -tr:
List files and sort by file size
Type the ls -South (the Southward is uppercase) command to listing files or directories and sort by size in descending society (biggest to smallest).
You can also add a -r flag to opposite the sorting order like and so: ls -Sr:
List files and output the effect to a file
Type the ls > output.txt command to print the output of the preceding command into an output.txt file. Y'all tin utilise any of the flags discussed before like -la — the key signal here is that the result will exist outputted into a file and not logged to the control line.
And so y'all can use the file as you lot come across fit, or log the contents of the file with cat output.txt:
Conclusion
There are tons of other commands and combinations you tin can explore to listing out files and directories based on your needs. Ane thing to remember is the ability to combine multiple commands together at one time.
Imagine you lot desire to list a file in long format, including hidden files, and sort by file size. The command would exist ls -alS, which is a combination of ls -l, ls -a, and ls -Southward.
If you forget any command or are unsure about what to practice, yous tin can run ls --help or man ls which will display a manual with all possible options for the ls command:
Thanks for reading!
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