How would a date command output null/nothing when the variable supplied has no/null value. I know if else statement can do this, but I kinda think it's not the proper way. Is there a decent command or alterations to the date command to do this?
E.g.
myDay=""
bDay=`date -d "$myDay"`
echo "$bDay" // this should have no output
You could do:
bDay=${myDay:+$(date -d "$myday")}
or:
if [ -n "$myDay" ]; then
bDay=$(date -d "$myDay")
else
bDay=
fi
or:
bDay=$([ -z "$myDay" ] || date -d "$myDay")
or (with an error message if $myDay is empty):
bDay=$(date -d "${myDay:?no date supplied}")
Note that echo (except for csh's echo) always outputs at least a newline character (unless you use -n or \c depending on the echo implementation), even when not passed any argument, so you'd also need:
[ -z "$bDay" ] || echo "$bDay"
for not outputting anything when $bDay is empty.
