Bash Cheatsheet

Bash (Bourne Again SHell) is the default command-line interpreter for most Linux distributions. It provides a powerful interface for interacting with the operating system through commands, scripts, and automation.

File operations in Bash include creating, manipulating, and managing files and directories. This section covers essential commands for working with files, managing permissions and ownership, searching through files, viewing file contents, and handling file compression.

Text processing in Bash involves manipulating and analyzing text data using specialized commands. These tools are essential for extracting, transforming, and analyzing data in text files and command outputs.

Process management in Bash involves listing, controlling, monitoring, and manipulating running processes. This includes sending processes to background, bringing them to foreground, and sending signals to control their behavior.

I/O redirection allows you to control where input comes from and where output goes. Bash has three standard file descriptors: standard input (stdin/0), standard output (stdout/1), and standard error (stderr/2).

Bash variables store data that can be referenced and manipulated throughout your script or shell session. They can hold strings, numbers, arrays, and more. Variables in Bash don't have explicit types and are treated as strings by default.

Control structures in Bash determine the flow of script execution. They include conditionals, loops, case statements, and functions that enable decision-making and code reusability in shell scripts.

Bash provides powerful built-in capabilities for string manipulation without requiring external tools. These operations are essential for text processing, variable handling, and data validation in shell scripts.

Bash provides several ways to perform arithmetic operations. The primary methods include using the `let` command, double parentheses `(( ))`, or the `expr` utility. Bash natively handles only integer arithmetic, but floating-point operations can be performed using external tools.

Shell scripting allows you to automate tasks by combining commands into executable files. Bash scripts can handle command line arguments, implement error handling, and create logs for debugging purposes.

Advanced Bash features provide powerful tools for complex scripting and command-line operations. These include pattern matching with regular expressions, efficient text expansion with brace notation, file globbing, process isolation with subshells, signal handling, and built-in commands that execute faster than external programs.

Bash provides powerful tools for network operations including connectivity testing, remote access, file transfers, and monitoring network traffic. These utilities allow system administrators and developers to manage remote systems and diagnose network issues directly from the command line.

System administration in Bash involves managing users, system resources, services, packages, and scheduled tasks. These commands help maintain and monitor Linux/Unix systems effectively.