I have the following bash code:
FULLSTR="/FOO/BAR/QUX"
IFS=/
ARY=($FULLSTR)
What I want to do is to concatenate the 2nd and 3rd element of ARY with
/ and assigned it into a variable. The end result I hope to get is /BAR/QUX.
But why this doesn't work:
NSTR=/${ARY[2]}/${ARY[3]}
echo $NSTR
It produces:
BAR QUX
What's the right way to do it?
The issue is in your echo $NSTR command: IFS is still set to /, so when $NSTR undergoes word-splitting and file-name expansion, the stuff on either side of a / becomes separate arguments to echo.
To fix this, I recommend finding a better way to set ARY to begin with, rather than starting with $FULLSTR. Parameter-expansions such as $FULLSTR should essentially always be quoted, because you essentially never want word-splitting and filename-expansion. (In your case you do want the word-splitting . . . but not the filename-expansion.)
If that's not an option — if your only way to set ARY is by splitting $FULLSTR — then you can write something like this:
OLDIFS="$IFS"
IFS=/
ARY=($FULLSTR)
IFS="$OLDIFS"
NSTR="/${ARY[2]}/${ARY[3]}"
echo "$NSTR"
Or, better yet, you can set NSTR directly based on $FULLSTR, and avoid ARY except when you have no choice:
NSTR="/${FULLSTR#/*/}"
echo "$NSTR"
