[SOLVED] What does $1 mean in shell scripts?

[ofbodur]

would someone please explain what does while ["$1"] mean in the code below? I see it many times in many scripts. What does it refer to?

I also wonder what if [ "$1" = "-i" ] means...

Code: Select all

#!/bin/bash

while [ "$1" ]
do
if [ "$1" = "-i" ] then
infile="$2"
shift 2
elif [ "$1" = "-o" ]
then
outfile="$2"
shift 2
else
echo "Program $0 does not recognize option $1"
fi
done
tr a-z A-Z <$infile >$outfile

[doktor5000]

Next time please use a more meaningful thread title, nobody will find your thread with that title via search function.

You probably should read some basics about shell scripting first. $1 is the first argument you pass to a script.

Check http://www.tldp.org/LDP/Bash-Beginners-Guide/html/
or http://tldp.org/HOWTO/Bash-Prog-Intro-HOWTO.html
or http://tldp.org/LDP/abs/html/

[ofbodur]

thanks doc

[doktor5000]

This wouldn't happen if you try to learn to walk before you want to run
Use one tutorial, and stick to it. The best that i've seen so far is http://steve-parker.org/sh/sh.shtml