Bash

Bash cannot return values, whether a single value or an array, but it can return a status (the same as other programs). However, there are multiple turnarounds that we can use to return an array from a function. Let’s explore them below. Using nameref Feature To return the entire array from a function in Bash: […]

Using date Command Use the date command to format the date to yyyymmdd in Bash. formatted_date=$(date +'%Y%m%d') echo $formatted_date 20230531 In the above example, the bash date command is used to get the current date with the format specifier '%Y%m%d' to specify the date format. In Bash, the date command is used to retrieve the […]

Using awk Command Use the awk command to get the last word of each line from a file in Bash. It is line1 It is line2 It is line3 It is line4 It is line5 awk '{print $NF}' input.txt line1 line2 line3 line4 line5 We use the awk command, a powerful text-processing tool allowing you […]

Every command we run successfully or unsuccessfully in Bash leaves a particular code behind, which we call an exit code or exit status. We use this code to analyze the last command in Bash. Using $? Variable Use shell variable, $?, to get the exit code of the last-run command in Bash. date exit_code=$? echo […]

Using Substitution Syntax Use Substitution Syntax ($(...)) to get output from a Python script and store it in a Bash variable. print("Welcome to Java2Blog!") result=$(python my_script.py) echo $result Welcome to Java2Blog! We used the command substitution syntax,$(command), to capture the output of the Python script (my_script.py) in a Bash variable (result). Here, the command was […]

Using Parameter Expansion Use parameter expansion to get everything after character in Bash. string="Hello World!" delimiter=" " output="${string#*$delimiter}" echo "$output" World! First, we set the string variable with a string type value; then, we initialised the delimiter variable with a space character (" "). The delimiter variable contained the character, after which we wanted to […]

1. Overview In scripting and programming, extracting specific portions of text from larger strings or files is a common task. In this article, we will see different ways to get text between two String using grep, awk, sed, and bash parameter expansion. 2. Introduction to Problem Statement We are given a String, and we need […]

Using sed Command with Substitutions Use the sed command with multiple substitutions to remove leading and trailing whitespaces from a single-line string in Bash. str=" It is an example line. " modified_str=$( echo "$str" | sed 's/^ *//;s/ *$//;') echo "|$str|" echo "|$modified_str|" | It is an example line. | |It is an example line.| […]

Using awk Command Use the awk command to print every nth line from file in Bash. This is 1st line This is 2nd line This is 3rd line This is 4th line This is 5th line This is 6th line This is 7th line This is 8th line This is 9th line This is 10th […]