Sometimes when you are redirecting the output of a command by piping to another command or to a file, you get the error messages. There are three standard I/O streams, which are used in Bash and other Linux shells when a program is executed. Below are the streams and each representing by the numberic...
The printf command have more control over the formatting of the output. It formats and prints arguments similar to the C printf() function. In this article we will see how to use printf command bash. printf Command# Bash and other shells like Zsh and Ksh have printf by default. The standalone binary /usr/bin/printf is...
Using the select construct you can generate menus. In this guide, we will discuss about the basics of the select construct in Bash. Bash select Construct# You can generate a menu from the list of items using the select construct. Following is the syntax for the select construct and it is similar to the...
It’s a best practice to make bash script in a clean and understandable way. You can make you code clean and arrange by indenting, blocks and giving related names of variables and functions. You can also improve the code readability using comments. Comments are human-readable explanation or short description. In this article we will...
Variable increment and decrement is fundamental arithmetic operation in bash scripting. It’s mostly used with the for, while and until loops. Increment means adding value to variable and Decrement means subtracting from numeric variable value. This article explains multiple ways to increment or decrement a variable. Use of + and - Operators# You must...
While you working with string in Bash need to check whether a string contains another string. In this guide, we will show you multiple ways to check if a string contains a substring in bash scripting. Use Wildcards# It is easy to use asterisk wildcard symbols (asterisk) * to compare with the string. Wildcard...
Arrays are set of data and fundamental requirement for any programming language. We can say that it’s a variable with multiple child variables. This article shows you basics and use of arrays in Bash scripts. Bash Arrays# One dimensional array with numbered index and associative array types supported in Bash. Those are referenced using...
At the time of writing of Bash scripts, sometimes you need to read a file line by line. In this tutorial, we will show you how to read file line by line in Bash. Syntax for Read File Line by Line# The following is the common syntax for reading a file line-by-line: Single line...
A Heredoc (Here document) is a redirection type which allows to pass multiline lines of input to a command. Sometimes while writing shell scripts you need to pass multiline block of code or text with the command like cat, sftp or tee. In this guide, you will learn how to use the Heredoc in...
In any programming language the concatenation is the commonly used string operations. String concatenate is used to joining the two or more strings together by appending one to end of another string. In this tutorial, you will learn how to concatenate strings in Bash. Concatenating Strings# It’s very easy to concatenate multiple string variables...