right align/pad numbers in bash

If you are interested in changing width dynamically, you can use printf's '%*s' feature

printf '%*s' 20 hello

which prints

               hello

Here's a little bit clearer example:

#!/bin/bash
for i in 21 137 1517
do
    printf "...%5d ...\n" "$i"
done

Produces:

...   21 ...
...  137 ...
... 1517 ...

For bash, use the printf command with alignment flags.

For example:

printf '..%7s..' 'hello'

Prints:

..  hello..

Now, use your discretion for your problem.

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