Shell – Run script in current shell without . before command

In tcsh, $_ at the beginning of the script will contain the location if the file was sourced and $0 contains it if it was run.

#!/bin/tcsh
set sourced=($_)
if ("$sourced" != "") then
    echo "sourced $sourced[2]"
endif
if ("$0" != "tcsh") then
    echo "run $0"
endif

In Bash:

#!/bin/bash
[[ $0 != $BASH_SOURCE ]] && echo "Script is being sourced" || echo "Script is being run"

You can use bash trap ERR to make your script quit if any command returns status greater than zero and execute your function on exiting.

Something like:

myfunc() {
  echo 'Error raised. Exiting!'
}

trap 'myfunc' ERR

# file does not exist, causing error
ls asd
echo 123

Note that bash trap ERR does implicit set -o errexit or set -e and is not POSIX.

And the ERR trap is not executed if the failed command is part of the command list immediately following until or while keyword, part of the test following the if or elif reserved words, part of a command executed in && or || list, or if the command’s return status is being inverted using !.