Scripting

The Backslash Escaping Problem in Awk Awk is a popular text processing language in Linux and UNIX systems. It is commonly used to parse and manipulate text files and output streams. Awk scripts often work closely with shell scripts to process shell variables and command outputs. A major issue arises when passing shell variables containing…

What Triggers the Shebang Line The shebang line, written as #! on the first line of executable scripts, indicates the interpreter that should execute the script. This directive tells the operating system to use the specified program to handle the script instead of trying to execute it directly. The shebang line ultimately triggers the corresponding…

What is the Shebang? The shebang refers to the two characters “#!” that start interpreter directive lines in Linux and other Unix-like operating systems. Acting as a marker, the shebang indicates to the system which interpreter should be used to execute the script that follows. Definition of the shebang The term “shebang” is derived from…

The Problem: Renaming Many Files is Tedious and Time-Consuming Renaming a large number of files one-by-one is an extremely tedious and inefficient process. When managing directories with thousands of files, renaming each individually can take hours of manual effort. There is a clear need for robust bulk and recursive renaming capabilities on Linux to optimize…

Understanding Escape Sequences An escape sequence is a combination of keyboard characters that does not represent a printable character but has a special meaning to be interpreted by the computer program that receives it. Escape sequences are used in many computing contexts such as programming languages and command shells to encode information in a compact…

What is Variable and Command Substitution? Variable substitution refers to the replacement of a variable with its value when a script or command is executed. In shells like Bash, variables can be defined and referenced using the $ notation – $MY_VAR will be replaced with the actual value of MY_VAR when the script runs. This…

Solving Common Bash Scripting Challenges Bash scripting provides a powerful way to automate tasks on Linux systems. However, without proper coding practices, Bash scripts can easily become fragile and prone to errors. By leveraging key language features like pipelines and loops, along with exception handling and modularization, you can write robust Bash scripts capable of…

Bash pipelines allow commands to be chained together by connecting the stdout of one process to the stdin of another. This allows efficient data processing flows to be constructed. However, variables set in one part of a pipeline are not always available further down the pipeline. This loss of variable scope is caused by subshells…

Defining The Problem: Variable Values Lost Across Pipelines Bash pipelines allow commands to be chained together by connecting the standard output of one command to the standard input of another. This enables efficient data processing flows. However, pipelines also create subshells for each command. As a result, variables set in one part of a pipeline…

Preserving Command History Across Sessions Being able to preserve the bash command history between sessions and logins can be invaluable for auditing, debugging, and productivity. Here we explore some methods to export the current history to a file, import history files automatically during login, and configure seamless command history persistence in bash. Exporting the current…