run_with_cache.sh

#!/bin/bash

BASE_DIR="$(dirname $0)/../.."
SCRIPT_DIR="$(dirname $0)/.."
DEP_DIR="$BASE_DIR/dependencies"

#######################################
# variables
#######################################

OUTPUT_FILE=
INPUT_FILE=
CACHE=1

DONT_RUN=
VERBOSE=
LOG_FILE=
PRINT_CMD=

CMD=()

#######################################
# functions
#######################################

function print_help {
	echo "USAGE:"
	echo
	echo "  $ $0 [OPTIONS] [--] CMD [OPT1 ...] [ARG1 ...]"
	echo
	echo "DESCRIPTION:"
	echo "  Run CMD optionally with '\$INPUT' and '\$OUTPUT' expanded as given by OPTIONS"
	echo
	echo "CACHING:"
	echo "  With caching enabled, CMD is only run"
	echo "  if the output file not yet exists"
	echo
	echo "OPTIONS:"
	echo "  -h | --help: print this help"
	echo "  -i|--input-file INPUT: if specified, expand '\$INPUT' when executing CMD"
	echo "  -o|--output-file OUTPUT: if specified, expand '\$OUTPUT' when executing CMD"
	echo "  -c|--cache CACHE: if true, only execute if OUTPUT doesn't exist"
	echo "  -l|--log-file LOG_FILE: write output to LOG_FILE"
	echo "  -p|--print-cmd: print the COMMAND being executed"
	echo "  -n|--dont-run: don't execute command"
	echo "  -v|--verbose: print additional information"
}

#######################################
# parse command line arguments
#######################################

while [[ $# > 0 ]]; do
	key="$1"
	case $key in
		-h | --help)
			print_help
			exit 0
			;;
		-i|--input-file)
			shift
			INPUT_FILE="$1"
			shift
			;;
		-o|--output-file)
			shift
			OUTPUT_FILE="$1"
			shift
			;;
		-c | --cache)
			shift
			CACHE="$1"
			shift
			;;
		-l | --log-file)
			shift
			LOG_FILE="$1"
			shift
			;;
		-p | --print-cmd)
			shift
			PRINT_CMD=1
			;;
		-n | --dont-run)
			shift
			DONT_RUN=1
			;;
		-v | --verbose)
			shift
			VERBOSE=1
			;;
		--)
			shift
			break
			;;
		-* )
			echo "wrong syntax!"
			print_help
			exit 1
			;;
		*)
			break
			;;
	esac
done

if [[ $# = 0 ]]; then
	print_help
	exit 1
fi

if [[ "$1" != "" ]]; then
	CMD=( "$@" )
fi

if [[ "$OUTPUT_FILE" = "" ]]; then
	print_help
	exit 1
fi

if [[ "$VERBOSE" != "" ]]; then
	echo "creating '"$(dirname "$LOG_FILE")"'"
fi
mkdir -p $(dirname "$LOG_FILE")

if [[ "$INPUT_FILE" != "" ]]; then
	INPUT="$INPUT_FILE"
fi
OUTPUT="$OUTPUT_FILE"
if [[ $CACHE ]] && [[ -e $OUTPUT ]]; then
	echo -n "(skipping) '"
	eval echo -n ${CMD[@]}
	if [[ "$LOG_FILE" != "" ]]; then
		echo -n " >'$LOG_FILE'"
		echo -n " 2>&1"
	fi
	echo "'"
else
	if [[ "$DONT_RUN" = "" ]]; then
		if [[ $PRINT_CMD ]]; then
			echo -n "executing: '"
			eval echo -n ${CMD[@]}
			if [[ "$LOG_FILE" != "" ]]; then
				echo -n " 2>&1"
				echo -n " >'$LOG_FILE'"
			fi
			echo "'"
		fi
		if [[ "$LOG_FILE" != "" ]]; then
			CMD+=( ">" "'$LOG_FILE'" )
			CMD+=( "2>&1" )
		fi
		eval "${CMD[@]}" || exit 1
	fi
fi