Apple - Can I configure terminal to show stderr output in different colour

There is no straightforward solution, but there are at least a few workarounds available to do this.

You can install hilite by building the single C file (hilite.c in this case) or by using brew install hilite (with homebrew installed on the system). Use it as hilite <command>.
You can use the command from this answer on serverfault (substitute command with the name of your script/command) to make stderr appear in red (for other colors, refer the ANSI escape sequences list and change the 31m in the below command accordingly):
```
command 2> >(while read line; do echo -e "\e[01;31m$line\e[0m" >&2; done)
```
You can use stderred to color stderr in red.

You may want to have a look at stderred which allows to output Stderr in red.

It's OSX compatible and there is a manual to install it on OSX.

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