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How are the loops used in bash scripting?
They are useful for automating repetitive tasks. There are 3 basic loop structures in Bash scripting which we’ll look at below. There are also a few statements which we can use to control the loops operation. One of the easiest loops to work with is while loops. They say, while an expression is true, keep executing these lines of code.
When to use until loop in shell scripting?
In the above until loop syntax, until, do, and done are built-in keywords of the shell scripting. This loop will do the same task as other loops are doing and it is almost similar to the while loop but in such situations, we need to use only until loop as it will be a better way to do that task rather than doing with while loop.
When to use break and continue in Bash?
Using Break and Continue in bash loops. Sometimes you may want to exit a loop prematurely or skip a loop iteration. To do this, you can use the break and continue statements. The break statement terminates the execution of a loop and turn the program control to the next command or instruction following the loop.
Which is the negation of a for loop in Bash?
Notice that the negation of the test condition [ $num -le 10 ]; is [ $num -gt 10 ]; If you are following this tutorial series from start, you should be familiar with arrays in bash. For loops are often the most popular choice when it comes to iterating over array elements.
Why do you use read and while in Bash?
Loops using read allow you to iterate through lines of a file that is to be generated or already exists. We have a command or function (lhs) that can generate lines in a file that can be looped through using read and a while loop. We have a file (rhs) with lines that can be looped through using read and a while loop.
How to read command line arguments in a bash script?
The script then reads the supplied arguments, parse and process them accordingly. In more advanced cases, you may want to pass command-line options to your script (e.g., “-h” or “-f my.txt”) to optinally change the default settings of the script.