AWK programs as executable script files

We can write self-contained AWK scripts to execute AWK commands, like we have with shell scripts to execute shell commands. We create the AWK script by using  #!, followed by the absolute path of the AWK interpreter and the -f optional argument. The line beginning with #! tells the operating system to run the immediately-followed interpreter with the given argument and the full argument list of the executed program. For example, we can update the cmd.awk file to emp.awk, as follows:

$ vi emp.awk
#!/usr/bin/awk -f
BEGIN { print "***Emp Info***" }
{ print }

Give this file executable permissions (with the chmod utility), then simply run ./emp.awk empinfo.txt at the shell and the system will run AWK as if you had typed awk -f cmd.awk empinfo.txt:

$ chmod +x emp.awk
$./emp.awk empinfo.txt 
***Emp Info***
Jack 9857532312 jack@gmail.com hr 2000 5
Jane 9837432312 jane@gmail.com hr 1800 5
Eva 8827232115 eva@gmail.com lgs 2100 6
amit 9911887766 amit@yahoo.com lgs 2350 6
Julie 8826234556 julie@yahoo.com hr 2500 5

Self-contained executable AWK scripts are useful when you want to write AWK programs that users can invoke without having to know it was written in AWK.