Bash: How to get a chain of calls by mistake?

Question

I have a traceback function in bash that works quite well (the code below), but the problem is that bash itself, when it gets into an error, does not provide backtracking or any information that will help identify the caller, which can help in debugging the problem.

eg:.

./c.sh: line 23: urgh: command not found

function backtrace () {
    local deptn=${#FUNCNAME[@]}

    for ((i=1; i<$deptn; i++)); do
        local func="${FUNCNAME[$i]}"
        local line="${BASH_LINENO[$((i-1))]}"
        local src="${BASH_SOURCE[$((i-1))]}"
        printf '%*s' $i '' # indent
        echo "at: $func(), $src, line $line"
    done
}

Is it possible to catch bash on such errors so that I can call my own function to get this output?

 at: c(), ./c.sh, line 22
  at: b(), ./c.sh, line 11
   at: main(), ./b.sh, line 5

Update: The final working version of the suggestions and trap traps on error:

function backtrace () {
    local deptn=${#FUNCNAME[@]}

    for ((i=1; i<$deptn; i++)); do
        local func="${FUNCNAME[$i]}"
        local line="${BASH_LINENO[$((i-1))]}"
        local src="${BASH_SOURCE[$((i-1))]}"
        printf '%*s' $i '' # indent
        echo "at: $func(), $src, line $line"
    done
}

function trace_top_caller () {
    local func="${FUNCNAME[1]}"
    local line="${BASH_LINENO[0]}"
    local src="${BASH_SOURCE[0]}"
    echo "  called from: $func(), $src, line $line"
}

set -o errtrace
trap 'trace_top_caller' ERR

Answer 1

Absolutely - this is exactly what error traps are for:

trap backtrace ERR

, - , trap 'backtrace "${#BASH_SOURCE[@]}" "${BASH_SOURCE[@]}" "${#BASH_LINENO[@]}" "${BASH_LINENO[@]}"' ERR, ( argv); , , .