You can use for loops in bash just like in any other programing language. The basic syntax is like this:
for variable-name in 1 2 3 do list-of-commands done
One line for loop in bash
To do a quick one-liner with for, we use a semicolon to separate each line. In this example, we will give for a list of 4 items to iterate through.
~$ for i in 1 2 3 4; do echo "This is line number $i"; done; This is line number 1 This is line number 2 This is line number 3 This is line number 4
For loop in a bash script
When writing a script. We don’t need to use the semicolon as in the example above. This time we write each part of the command on a separate line. This example will print exactly the same output as the one-liner we just did.
for i in 1 2 3 4 do echo "This is line number $i" done
Use a command to get a list of items
Instead of giving for a long list of items to iterate through, we can also wrap a command in $( ) to get the list. In this example we use the seq command to get a list of numbers 1 through 4. This will output exactly the same as above.
for i in $( seq 1 4 ) do echo "This is line number $i" done