Question

I think generate temp file may slower and if user press ctrl+c the temp file will become garbage.

Here is my original code

for f in bin/* ; do
  ldd $f 2>/dev/null | awk '{print $1}'
done | sort -u | grep -v -e '^not$' -e 'ld-linux' > list.1
while read soname ; do
  process_so_name $soname
done < list.1

Is it possible to remove the temp file list.1?

Answer 1

Just do it without a temp file. Pipe the result of the last grep into the while.

You can hook into SIGINT to detect Ctrl+C, but why worry if you don’t need to? You still won’t be able to hook into SIGKILL.

for f in bin/* ; do
  ldd $f 2>/dev/null | awk '{print $1}'
done | sort -u | grep -v -e '^not$' -e 'ld-linux' | while read soname ; do
  process_so_name $soname
done

You can make this look more recognizable by placing the loops in functions (you can do this in a script file or right in the shell):

step_1() {
  for f in bin/* ; do
    ldd $f 2>/dev/null | awk '{print $1}'
  done
}

step_2() {
  while read soname ; do
    process_so_name $soname
  done
}

step_1 | grep -v -e '^not$' -e 'ld-linux' | step_2

To hook into SIGINT, do something like this:

trap "echo SIGINT; rm -f tempfile; exit -1" INT

To hook into SIGTERM (see comments underneath), do this:

trap "echo SIGTERM; rm -f tempfile; exit -1" EXIT