A script which performs some code style checking (line length, trailing spaces, etc.)

check-code

#!/bin/bash
#######
# A script which finds various code violations (such as line spacing or trailing spaces)
#
_SCRIPT="${0}"
_QUIET=""; _TRAIL_ONLY=""; _EMPTY=""; _LENGTH_ONLY=""; _MAX_LENGTH=120; _PATHS=(); _ERR=""

_err () { "${_SCRIPT}" __XXX__ "$@"; exit $?; }

while [ $# -gt 0 ]; do
    case "${1}" in
        "-h"|"--help"|"__XXX__")
            if [ "${1}" == "__XXX__" ]; then
                _O=/dev/stderr; _R=1; _MSGS=("$@")
                if [ ${#_MSGS[@]} -gt 1 ]; then
                    echo "Error:" >${_O}
                    for ((i = 1; i < ${#_MSGS[@]}; i++)); do echo "    ${_MSGS[${i}]}" >${_O}; done
                    echo "" >${_O}
                fi
            else
                _O=/dev/stdout; _R=0
            fi
            echo "Usage: ${0} [options...] <path> [path...]"                                                >${_O}
            echo ""                                                                                         >${_O}
            echo "Options:"                                                                                 >${_O}
            echo "    -h, --help                    Shows this help"                                        >${_O}
            echo "    -q, --quiet                   Show less output"                                       >${_O}
            echo "    -t, --trailing-only           Only run the trailing space check"                      >${_O}
            echo "    -e, --match-empty             Matches all whitespace (empty) lines as trailing space" >${_O}
            echo "    -l, --length-only             Only run the line length check"                         >${_O}
            echo "    -m, --max-length <length>     Use <length> as the line length max (default 120)"      >${_O}
            echo ""                                                                                         >${_O}
            exit 1;
            ;;
        "-q"|"--quiet")
            _QUIET="y"
            ;;
        "-t"|"--trailing-only")
            [ -z "${_LENGTH_ONLY}" ] || _err "Cannot set -t and -l together"
            _TRAIL_ONLY="y"
            ;;
        "-e"|"--match-empty")
            _EMPTY="y"
            ;;
        "-l"|"--length-only")
            [ -z "${_TRAIL_ONLY}" ] || _err "Cannot set -t and -l together"
            _LENGTH_ONLY="y"
            ;;
        "-m"|"--max-length")
            shift; [ "${1}" -eq "${1}" ] 2>/dev/null || _err "Invalid max-length '${1}'"
            _MAX_LENGTH=${1}
            ;;
        *)
            [ -e "${1}" ] || _err "Path '${1}' does not exist"
            _PATHS+=("${1}")
            ;;
    esac
    shift
done

if [ ${#_PATHS[@]} -eq 0 ]; then _err "At least one path should be set"; fi

if [ -z "${_LENGTH_ONLY}" ]; then
    [ -z "${_QUIET}" ] && {
        echo "==================================================="
        echo "Lines with trailing spaces:"
        echo "----------------------------"
    }
    if [ -n "${_EMPTY}" ]; then
        grep --color -Irn '^.* \+$' ${_PATHS[@]} && _ERR="y" || {
            [ -z "${_QUIET}" ] && echo "No violations";
        }
    else
        grep --color -Irn '^.*[^ ] \+$' ${_PATHS[@]} && _ERR="y" || {
            [ -z "${_QUIET}" ] && echo "No violations";
        }
    fi
    [ -z "${_QUIET}" ] && echo ""
fi

if [ -z "${_TRAIL_ONLY}" ]; then
    [ -z "${_QUIET}" ] && {
        echo "==================================================="
        echo "Lines with length > ${_MAX_LENGTH}:"
        echo "----------------------------"
    }
    grep --color -Irn "^.\{${_MAX_LENGTH},\}\$" ${_PATHS[@]} && _ERR="y" || {
            [ -z "${_QUIET}" ] && echo "No violations";
        }
    [ -z "${_QUIET}" ] && echo ""
fi

[ -z "${_ERR}" ] || {
    echo "!!! Found violations !!!" >&2
    echo "" >&2
    exit 1
}