Let’s start with the first example of using the “while” loop on one line of the Bash code. As the file is empty, we need to add the Bash extension in our Bash file to make it execute as a “Bash” script. It is not essential to add the extension. Your code will execute perf...
While loop is one of them. Like other loops, a while loop is used to do repetitive tasks. This article shows how you can use a while loop in a bash script by using different examples. Syntax of while loop: while [ condition ] do commands done The starting and ending block of th...
Here we add the number1to a file nameda, and check for the existence of the number1within that file using agrep -q(a quiet grep). We keep doing so (i.e.while) until it is no longer true. Whilst it is true, we print the textyesand pause the loop for five seconds withsleep 5....
InBashscripting, there are 3 types ofloops:for loop,while loop, anduntil loop. The three are used to iterate over a list of values and perform a given set of commands. In this guide, we will focus on theBash For Loopin Linux. Bash For Loop Syntax As mentioned earlier, thefor loopit...
# use $line variable to process line echo $line done exec 0<&3 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. You can easily evaluate the options passed on the command line for a script using while loop: ... .. while getopts ae:f:hd:s:qx: option do case...
You can easily evaluate the options passed on the command line for a script using while loop: ... .. while getopts ae:f:hd:s:qx: option do case "${option}" in a) ALARM="TRUE";; e) ADMIN=${OPTARG};; d) DOMAIN=${OPTARG};; f) ...
There are various loops constructs such as the while loop, the until loop, the select loop, and the for loop. However, in this article, we will focus on the widely popular ‘the for loop.’ It will cover how and when to use the ‘for pool’ tool. Aforementioned, Loops are set of ...
While Read Line Loop in Bash The generalwhile read lineconstruction that can be used in Bash scripts: while read LINE do COMMAND done < FILE The same construction in one line (easy to use on the Linux command line): while read LINE; do COMMAND; done < FILE ...
There are times when you have a file having thousands of lines but what if you want to count the number of the lines? You can use the while loop in that case: #!/bin/bash filename="example.txt" line_count=0 while IFS= read -r line; do ...
1. A simple while loop Imagine that you're installing a huge application, and you're concerned that it may eventually use too much space on the file system. Instead of runningdfin a separate terminal, you can run a simple command to monitor the disk utilization every second. This allows ...