CODEWITHSUNDEEP
bashshell
z0mb1e_kgd
z0mb1e_kgd

Reputation: 13

Cannot get proper exit code from $?

I am writing a backup bash script, and organize it as a set of several .sh files (each of them executing one function) that are called from the main .sh file (like libraries in any conventional PL). One of them is a logging script that is to take an exit code of the previously executed command and if it succeeds the script logs one message, and if it doesn't - logs another.

However, if I check $? within the logging script, I always get 0 code regardless of the previous command's result in the main script. As far as I understand the process, calling the script from an outer file makes it being executed in a different subshell that has $? with 0 value as nothing failed within that very subshell.

#main.sh:

command; log.sh "message" "error"

#log.sh:

if [ "${?}" -eq "0" ]; then
  printf "${1}\n" >> main.log
else
  printf "${2}\n" >> main.log
fi

The $? is always 0, so it always logs a success message. How do I get the actual exit code of the "command" above?

I might store it in some file and read the file in the beginning of the log.sh, but I feel there is a better solution.

Upvotes: 1

Views: 69

Answers (2)

codeforester
codeforester

Reputation: 42999

As stated by you, since log.sh is a script, it executes in a separate shell and hence $? of the caller is not visible to it. When a script starts, $? is 0 initially.

You can wrap your logging functionality into a function so that $? is visible to it:

log() {
    if [ "${?}" -eq "0" ]; then
      printf "${1}\n" >> main.log
    else
      printf "${2}\n" >> main.log
    fi
}

But it is better to pass $? explicitly as suggested by @cyrus.

You may want to take a look at the logging and error handling functionality implemented here:

https://github.com/codeforester/base/blob/master/lib/stdlib.sh

Upvotes: 2

Cyrus
Cyrus

Reputation: 88553

Replace

command; log.sh "message" "error"

with

command; log.sh "message" "error" "$?"

and

if [ "${?}" -eq "0" ]; then

with

if [ "$3" -eq "0" ]; then

Upvotes: 2

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