Just for kicks, here's an implementation of "if-then-else" called "ite", as a
function. Note that:
1) It is pretty much a drop in for the missing functionality (in the usual
${var:X} syntax), when used inside $().
2) All of the existing ${var:X} syntaxes are special cases of ite() and
could be
written in ite() instead.
--- Cut Here ---
# An implementation of a "if-then-else" for things like ${var-default value}
# Usage: value=$(ite varname "if string" "else string")
# If varname ends with a :, then use :+ instead of plain + for the test.
ite() {
[ $# = 3 ] || { echo "Wrong # of args ($#) - must be exactly 3!" >&2;
return 1; }
case $1 in
*:) declare -n var=${1%?} || return; [ "${var:+x}" ] ;;
*) declare -n var=$1 || return; [ "${var+x}" ]
esac
echo "${@:($?+2):1}"
}
--- Cut Here ---
Sample usage:
$ ite foo "foo is set to '$foo'" "foo is unset"
$ ite foo: "foo is set to '$foo'" "foo is null or unset"
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