Posted By: Anonymous
I need to check the existence of an input argument. I have the following script
if [ "$1" -gt "-1" ] then echo hi fi
[: : integer expression expected
How do I check the input argument1 first to see if it exists?
if [ $# -eq 0 ] then echo "No arguments supplied" fi
$# variable will tell you the number of input arguments the script was passed.
Or you can check if an argument is an empty string or not like:
if [ -z "$1" ] then echo "No argument supplied" fi
-z switch will test if the expansion of
"$1" is a null string or not. If it is a null string then the body is executed.