My Bash functions

my_bash_functions.sh

# (Generated by GPT-5)
# Returns the directory of a script file, resolving any symlinks,
# and normalizing to the physical path (no symlink components).
# Usage:
#   SCRIPT_DIR="$(script_dir)"                          # when function is defined in the same script
#   SCRIPT_DIR="$(script_dir "${BASH_SOURCE[0]}")"      # get caller's script dir (recommended if sourced from a lib)
# Notes:
#   - Bash only (uses BASH_SOURCE and [[ ]]).
#   - Works on macOS and Linux without relying on 'readlink -f'.
#   - For process substitution or stdin execution, there may be no real file path.
script_dir() {
    local src="${1:-${BASH_SOURCE[0]}}"
    # Follow symlinks
    while [ -h "$src" ]; do
    # Resolve the directory of the current link (physical)
    local dir
    dir="$(cd -P "$(dirname "$src")" && pwd)" || return
    # Read the symlink target (BSD/macOS-compatible; no '-f')
    src="$(readlink "$src")" || return
    # If the target is relative, make it absolute based on the previous directory
    [[ $src != /* ]] && src="$dir/$src"
    done
    # Return the physical directory of the final real file
    cd -P "$(dirname "$src")" && pwd
}
# Variant: write the result directly into a named variable (no subshell needed).
# Usage:
#   script_dir_into SCRIPT_DIR                    # same file
#   script_dir_into SCRIPT_DIR "${BASH_SOURCE[0]}"  # caller's script (recommended when sourced)
script_dir_into() {
    local __var="$1"; shift || true
    # Prefer an explicit src when provided; otherwise try the caller's file,
    # falling back to this function's file.
    local __src="${1:-${BASH_SOURCE[1]:-${BASH_SOURCE[0]}}}"
    local __dir
    __dir="$(script_dir "$__src")" || return
    # Bash 3.1+ (macOS 3.2 is OK): assign without eval
    printf -v "$__var" '%s' "$__dir"
}

# example usage:
# SCRIPT_DIR="$(script_dir)"
# echo $SCRIPT_DIR