Problems with bash variable expanding with single quotes

Question

I have a variable that I build like this :

ATTSTR=""
for file in $LOCALDIR/*.pdf
do
  ATTSTR="${ATTSTR} -a \"${file}\""
done

The variable now contains (notice the whitespaces in the file name) :

ATTSTR=' -a "/tmp/Testpage - PDFCreator.pdf"'

And now I want to use this variable in a command like this one :

mutt -s "Subject" "${ATTSTR}" [email protected]

But it turns out that it expands like this, and thus the command fails (notice the added single quotes surrounding the expanded variable):

mutt -s "Subject" ' -a "/tmp/Testpage - PDFCreator.pdf"' [email protected]

I want my variable expanded without the single quotes, using "$ATTSTR" or $ATTSTR is just worse. How can I achieve this ?

Answer 1

Filenames are notoriously unreliable in expanded strings; resist this temptation.

Instead, use an array to keep the filenames intact, regardless of any whitespace:

arr=()
for f in $somedir/*.pdf
do
arr+=( -a "$f")
done

# and for usage/display:

mutt -s mysubject "${a[@]}" some@body

See the Bash Guide on Arrays for reference.

Answer 2

Use eval function

command="mutt -s \"Subject\" $ATTSTR [email protected]"
response=$(eval "$command")