Unfortunately, this is not easy to solve in a portable way. The standard technique looks like this (substitute /usr/bin/awk for your awk path):
#!/usr/bin/awk -fBEGIN { if (!len) len = 1; end = start + len }{ for (i = start; i < end; i++) { print $1 } }The hard-coded awk path and non-standard -f flag, makes this not portable across all *nixes. If you are only ever going to run your script on one machine, then this may work fine. However, to make a portable awk script, you will need to wrap it in a shell script. Here are two ways that you can do it in one file:
The first way is standard and easy to read:
#!/bin/shawk 'BEGIN { if (!len) len = 1; end = start + len }{ for (i = start; i < end; i++) { print $1 } }'"$@"Unfortunately, this falls short in two key ways:
- If your awk script contains a
'character, you will need to type it like this:'"'"'to "escape" it. - If you are using a text editor with syntax highlighting, you will not get your awk script properly highlighted.
Another solution, is to use sed to strip out the sh wrapper:
#!/bin/shexec awk "$(sed '1,2d'"$0")""$@"BEGIN { if (!len) len = 1; end = start + len }{ for (i = start; i < end; i++) { print $1 } }This is something like a two line shabang header. It calls awk using the file from line 3 down as the script argument. This allows you to keep your pretty syntax highlighting and you can still use ' characters to your heart's content. The two downsides I see are:
- Arguably this is non-intuitive to read.
- If you are using a code linter, it may not like this.
