Test whether absolute path in variable

Shell Programming and Scripting
1

I'm using the following line in bash to test whether an argument supplied is an absolute path or not:

if echo $1 | grep '^/' > /dev/null
then
absolute=1
else
absoute=0
fi

The line appears to work but seems somewhat unprofessional looking to me. Is it an acceptable way to test this or is there some more advisable way?

2

Bash and Ksh solution:

if [[ "$1" = /* ]]
then
   : # Absolute path
else
   : # Relative path
fi

Jean-Pierre.

3

The fastest and most portable way (which will work in any Bourne-type shell, e.g., sh, bash, ksh, ash) is:

case $1 in
     /*) absolute=1 ;;
     *) absolute=0 ;;
esac