Shell

This article will show you how to split a string at a given delimiter in Bash/Shell scripts and show some examples. Splitting strings is a handy function to have available when crafting your scripts. CSV (Comma Separated Values) is a common format in which data is made available online, where data fields in a table are separated by (surprise) commas. You may also simply be looking to split a sentence into words at the spaces, or split paragraphs into sentences at the period, and so … Read more

The wc program can be used in Bash scripts and from the Linux command line to count the number of bytes, characters, words, or lines in a file. Here’s how to use it, with examples. wc Program Syntax The syntax for the wc command is as follows: wc OPTIONS FILE Note that: OPTIONS should be provided from the below table of available options FILE is the path to the file which will have the contents counted More than one file can be specified If more than one file is specified, the total … Read more

The Bash echo command serves a simple purpose – it outputs (echos) text. Here’s how to use it, with examples. echo Command Syntax The echo command is very simple and has the following syntax: echo OPTIONS TEXT Note that: OPTIONS should be one of the following options -n Do not output a trailing newline -e Enable interpretation of backslash escapes This means that escape characters can be used to insert special characters into the output \\ backslash \a alert (BEL) \b backspace \c produce no further output \e escape \f form feed \n new line \r carriage return \t horizontal tab \v vertical … Read more

This article will show you how to use while loops in Bash/Shell scripts, and provides some code examples. Bash scripts let you automate tasks in the linux shell. Often, you’ll want to repeat a task for a set of data or repeated user input – that’s what while loops are for – they let you loop or iterate over a sequence of data or input, making it easy to build scripts that repeat a set of actions. The while loop syntax demonstrated below will also work for the Zsh shell and … Read more

The case statement is used to choose which code to execute based on the value of a variable or expression. Here is how to use it in your Bash scripts. What Does the case Statement Do? The case statement is a convenient alternative to using multiple if/if else statements when you are deciding what action to take based on the value of a variable or expression. For example, if you have a variable called weekday, you can executed different code based on which day of the week is named in the variable, … Read more

We’ve zipped files from the Linux command line; now, let’s unzip them. This short article will show you how. Zipping Files Zipping files is common parlance for compressing one or more files or directories into a .zip file – a compressed file format. We cover how to do that in this article, so there’s no need to repeat too much of it here. The Unzip Command The unzip command may not be installed on your system by default. If it isn’t, it can be installed on Debian/Ubuntu-based OS by running: … Read more

This tutorial will show you how to set environmental variables in Bash/Shell scripts using the export keyword. Generally, variables declared in Bash/Shell scripts exist only within the scope of that running Bash/Shell script. To make them available elsewhere, they can be set as an environmental variable – meaning that the variable will be available when executing commands outside of the script on your system – for example, making the variable available from the command line after the script has completed. The export keyword does this – … Read more