HP-UX *** B.11.31 U ia64 **** unlimited-user license Hello,
var1=abc
var2=xyz
touch $var1 $var2 $var3
if the one of the variable is not set the command fails with
ksh: var3: parameter not set
How do we make the command ignore the variable that is not set/defined and create the files for the variables that are defined. Without if loops. Just within the touch command. Thanks
You'd get that error message if you had turned the -u option either by invoking ksh as ksh -u or ksh -o nounset or by running set -u or set -o nounset.
touch $var1 $var2 $var3
is wrong anyway unless those variables are meant to contain lists of file patterns.
It should have been:
touch -- "$var1" "$var2" "$var3"
Now, if you want to allow one of them to be empty and not pass it as an empty argument to touch in that case (and work around set -u), you'd write:
touch -- ${var1:+"$var1"} ${var2:+"$var2"} ${var3:+"$var3"}
Another option is to do:
(IFS=; set -f +u; touch -- $var1 $var2 $var3)
With IFS=, we disable word splitting, with set -f globbing, but we rely on the third side-effect of leaving variables unquoted: empty removal. (and we also disable nounset with set +u, all of that in a subshell only).
I doubt if you can do it just in a line, you can try something like this
validate_touch()
{
for value in "$@"
do
if [ ! -z "$value" ]; then touch $value;fi
done
}
validate_touch new
