How to untrap after a trap command

Question

I have an error trap as follows:

trap failed ERR function failed {     local r=$?     set +o errtrace     set +o xtrace     echo "###############################################"     echo "ERROR: Failed to execute"     echo "###############################################"     # invokes cleanup     cleanup     exit $r } 

There is a part of my code where I do expect an error:

command1 command2 command3 set +e #deactivates error capture command4_which_expects_error set -e #re-activates error capture command5 

Overall I need to ignore the trap during the execution of command4_which_expects_error

The set +e does not seem to disable the trap. Any other ways to "untrap" and then "re-trap" ?

Answer 1

Here is what you can find in the trap manual:

The KornShell uses an ERR trap that is triggered whenever set -e would cause an exit.

That means it is not triggered by set -e, but is executed in the same conditions. Adding set -e to a trap on ERR would make your script exit after executing the trap.

To remove a trap, use:

trap - [signal] 

Answer 2

To ignore the failure of a command that you know may fail (but don't necessarily need), you can cause the line to always succeed by appending || true.

Example:

#!/bin/bash  set -e  failed() {     echo "Trapped Failure" } trap failed ERR  echo "Beginning experiment" false || true echo "Proceeding to Normal Exit" 

Results

Beginning experiment Proceeding to Normal Exit