How to tell mutt not to wait for an attachment program to return?

Question

I use this line for images in my mailcap:

image/*; eog %s &;

but mutt immediately deletes the temp file and eog can’t load it.
When I remove the & mutt waits for eog to be closed until it escapes from the command line.

Answer 1

You could use a wrapper command that:

1. renames the file
2. runs the viewer in background
3. cleans up when the viewer has returned instead of letting mutt do it.

Something like:

#! /bin/sh -

TMPDIR=$(
  mutt -D 2> /dev/null |
    awk -F\" '
      $1 == "tmpdir=" {
        gsub("~", ENVIRON["HOME"], $2)
        print $2
        exit
      }'
)
[ -n "$TMPDIR" ] || exit
export TMPDIR

nargs=$#
nfiles=0
for i do
  case $i in
    ("$TMPDIR"/?*)
      new_file=$(mktemp -ut "XXXXX${i##*/}") &&
        mv -- "$i" "$new_file" &&
        nfiles=$(($nfiles + 1)) &&
        set -- "$new_file" "$@" "$new_file" &&
        continue
  esac
  set -- "$@" "$i"
done

run_command() (
  shift "$(($nargs + $nfiles))"
  exec "$@"
)

(
  run_command "$@"
  while [ "$nfiles" -gt 0 ]; do
    set -- "$@" "$1"
    shift
    nfiles=$(($nfiles - 1))
  done
  shift "$((2*$nargs))"
  rm -f -- "$@"
) &

And put something like:

image/*; muttv eog %s;

Where muttv is that script above.

The above makes no assumption on where the filename(s) appear(s) in the list of arguments or what character they contains... Which is why we first ask mutt what its tmpdir is (so we use that to determine what are the files to view).

In most cases, it would be overkill though, and as Gilles points out may not work if tmpdir is specified as relative to your mailbox folder.

A simpler one would be:

#! /bin/sh -
nargs=$#
eval "file=\${$nargs}"
newfile=$(dirname -- "$file")/new-$(basename -- "$file")
while [ "$nargs" -gt 1 ]; do
  set -- "$@" "$1"
  shift
  nargs=$(($nargs - 1))
done
shift
mv -- "$file" "$newfile" || exit
(
  "$@" "$newfile"
  rm -f -- "$newfile"
) &

Replace mv with cp if you don't want to touch the original file provided by mutt.