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Basanta Bhusan Khadka
Basanta Bhusan Khadka

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Shell Scripting: Basic Commands to just get you start scripting

Shell scripting is a powerful scripting language that operates within a shell environment, allowing users to automate repetitive tasks, manage files and directories, configure systems, and execute a series of commands in a single script.

Essential Shell Commands: A Practical Guide

Mastering shell commands provides the foundation to harness the power of shell scripting. Here’s a comprehensive guide to the key commands you’ll rely on for efficient file management, system monitoring, text processing, and more.

File and Directory Management

Create a Directory

mkdir new_directory
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: Creates a new directory in the current location.

Navigate Directories

cd new_directory
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: Changes to the specified directory.

cd ..
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: Returns to the previous directory.

List Directory Contents

ls
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: Lists files and folders.

ls -l
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: Lists detailed information about files (permissions, size, date).

ls -a
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: Lists all files, including hidden ones.

Copy Files and Directories

cp source_file.txt destination.txt
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: Copies a file to a new location.

cp -r source_directory destination_directory
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: Recursively copies an entire directory.

Move or Rename Files

mv oldname.txt newname.txt
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: Renames a file.

mv file.txt /path/to/destination/
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: Moves a file to a specified directory.

Delete Files and Directories

rm file.txt
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: Deletes a file.

rm -r directory/
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: Deletes a directory and its contents (use with caution).

File Content Operations
Display File Contents

cat file.txt
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: Displays file contents.

head file.txt
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: Shows the first 10 lines of a file.

tail file.txt
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: Shows the last 10 lines of a file.

Search within Files

grep "search_term" file.txt
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: Searches for specific text within a file.

grep -r "search_term" directory/
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: Searches within a directory recursively.

Edit a File

vim file.txt
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: Opens a file in Vim editor.

nano file.txt
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: Opens a file in Nano editor.

File Permissions and Ownership
Set File Permissions

chmod 755 file.txt
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: Sets read, write, execute permissions for the owner and read/execute for others.

Change File Ownership

chown user
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:group file.txt: Changes file ownership.

System Information and Monitoring
Print Working Directory

pwd
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: Shows the current directory path.

Check Disk Usage

df -h
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: Displays disk space usage in a human-readable format.

du -h directory/
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: Shows the size of a specific directory.

System Information

uname -a
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: Provides system information.

top
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: Real-time process monitor.

ps -ef
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: Lists running processes.

Network and Connectivity Commands
Network Connectivity Check

ping example.com
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: Checks if a host is reachable.

View Network Configuration

ifconfig
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: Displays network interfaces (use ip a on newer systems).

Compression and Archiving
Create Archives

tar -cvf archive.tar directory/
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: Creates a tar archive.

tar -czvf archive.tar.gz directory/
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: Creates a compressed (gzip) tar archive.

Extract Archives

tar -xvf archive.tar
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: Extracts a tar archive.

tar -xzvf archive.tar.gz
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: Extracts a gzip-compressed tar archive.

Advanced Utilities
Output Redirection

command > output.txt
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: Redirects output to a file (overwrites).

command >> output.txt
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: Appends output to a file.

Command Chaining and Piping

ls -l | grep "search_term"
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: Pipes output of one command into another.

Set Environment Variables

export VAR_NAME="value"
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: Sets an environment variable.

Command History

history
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: Displays command history.

With these essential commands, you’re well-equipped to start scripting effectively in the shell environment. Mastering these commands opens up the potential for automation, efficient file handling, and streamlined system administration through shell scripting.

Top comments (1)

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rohit_prasain profile image
Rohit Prasain

very insightful.