Thursday, August 24, 2017

Enable tracing on bash scripts

With shell scripts, it becomes difficult at times to debug which command took too long, or at which step has an issue. Even though I add generous amount of debug logs there are times where -x (execution trace) is invaluable. But I don't want to litter my regular logs with the -x output either!
So, after a bit of search found this nice snippet of bash:

trace_file() {
    exec 4>>"$1"
    set -x

With this function defined, I can invoke it in any script, with the path to trace file:

trace_file /tmp/mytrace