Which is the simple looping statement?
Basic loop structure encloses sequence of statements in between the LOOP and END LOOP statements. With each iteration, the sequence of statements is executed and then control resumes at the top of the loop.
What is needed for a for loop?
A for loop has two parts: a header specifying the iteration, and a body which is executed once per iteration. The header often declares an explicit loop counter or loop variable, which allows the body to know which iteration is being executed.
Which is loop statement?
A loop statement is a series of steps or sequence of statements executed repeatedly zero or more times satisfying the given condition is satisfied. Loop statements in programming languages, such as assembly languages or PERL make use of LABEL’s to execute the statement repeatedly.
When to use a loop in a script?
If we want to perform an operation multiple times with a single variable change or based on a condition then we need to write the logic number of times. So, instead of that, we can use loops to perform an operation a certain number of times.
How to run a for loop in shell?
Now let’s run the shell script… This simple example loops through each value (host) in myhosts, which is assigned to the shell variable HOSTFILE, and prints the hostname to standard output. Your scripts will obviously do more than just print the value stored in the for loop’s variable, but I think you get the idea.
Which is the best example of a while loop?
The second while loop example will likely be more useful to you. Shell scripts will frequently need to read the contents of a file, line by line, and store each line in a shell variable for additional processing. Using a while loop coupled with a read statement is a perfect way to accomplish this task.
What are the variables in the for loop?
In the above code, the following variables are used: index contains the current “counter” value. start_value is the first number (often 1 or 0) end_value is the last number (often the length of an array) by_count is how much to add to index_variable each time.