a template for making single-step deployment scripts

single_step.sh

#!/bin/bash

        ######## begin single-step debugging mechanism ########
        DEBUG_COLOR_ONE="\e[47;30m"         # gray background, black foreground
        DEBUG_COLOR_TWO="\e[0;1;31m"        # black background, bright red foreground
        function _trap_DEBUG() {
            echo -e "\n$DEBUG_COLOR_ONE$1\e[0m $DEBUG_COLOR_TWO$BASH_COMMAND\e[0m";
            read -s _ignore
        }
        # prefix a command with this to indicate that specific command should
        # be skipped when $IS_DRY_RUN is true
        function DRY_RUN() {
            if [ "$IS_DRY_RUN" ]; then
                echo "(skipped because this is a dry run)"
            else
                eval "$@"
            fi
        }
        echo "======== to single-step, press enter before each command is run ========"
        # other things that could go on this line:
        #   "DEBUG level:$SHLVL"
        #   "subshell-level: $BASH_SUBSHELL"
        #   "function:${FUNCNAME[0]:+${FUNCNAME[0]}(): }"
        trap '_trap_DEBUG "$BASH_SOURCE line $LINENO:"' DEBUG
        ######## end single-step debugging mechanism ########


# set to a non-empty string to avoid making any actual changes
IS_DRY_RUN=

echo test one two three
DRY_RUN touch /tmp/test123
echo hi
DRY_RUN rm -f /tmp/test123