# which - busca comando en PATH
 
oldpath=$PATH
PATH=/bin:/usr/bin
case $# in
0) echo "Use: which comando"; exit 2
esac
 
for i in `echo $oldpath|sed 's/:/ /g'`
do
    if test -f $i/$1
    then
        echo $i/$1
        exit 0    # lo encontramos
    fi
done
exit 1 # no se encontró