How can I know if the set -e option is enabled or not?

Question

I'm writing a shell function that will be called from many different places and I want to ignore all errors occurring inside the function disabling the (possibly enabled) set -e shell option, executing set +e.

The problem is that I don't know if that option was set or not, so I don't know if it's really needed to disable it, and more important, if I need to set it again at the end.

So, how do I know if it is set or not? Is there any way to ignore errors of all commands inside a shell function ignoring the -e shell option if is set?

Answer 1

Look at the value of $-, if it contains an 'e', then the '-e' option is set. This variable contains a list of all set options. This is described in the bash man page.

Answer 2

From man bash:

CONDITIONAL EXPRESSIONS
...
   -o optname
      True if the shell option optname is enabled. 
...

Which means, that this will do it:

if [ -o errexit ]
then
   ....
fi

and is much more clear than the rest of the alternatives.

PS: for optnames, look in man bash for option-name:

-o option-name
...
   errexit Same as -e.

Answer 3

I like both answers. Ansgar's suggestion works well with bash, Trevor's is good if grep is in the PATH. If you want to be independent of shell (bash/sh) and PATH you could use

[ "${-#*e}" != "$-" ]