Get stack trace in Bash shell script/program.

stack_trace.sh

# LICENSE: MIT, wtfpl or whatever OSS license you like
function get_stack() {
    local STACK=""
    local i message="${1:-""}"
    local stack_size=${#FUNCNAME[@]}

    # to avoid noise we start with 1 to skip the get_stack function
    for (( i=1; i<stack_size; i++ )); do
        local func="${FUNCNAME[$i]}"
        local linen="${BASH_LINENO[$(( i - 1 ))]}"
        local src="${BASH_SOURCE[$i]}"
        [ "x${func}" = x ] && func=MAIN
        [ "x${src}" = x ] && src=not-a-file
 
        STACK+=$'\n'"   at: '${func}' '${src}' '${linen}'"
    done

    echo "${message}${STACK}"
}