standard-funcs-sh

get_key()
{
    [ -t 0 ] && {  ## Check whether input is coming from a terminal
        [ -z "$_STTY" ] && {
            _STTY=$(stty -g)  ## Store the current settings for later restoration
        }

        ## By default, the minimum number of keys that needs to be entered is 1
        ## This can be changed by setting the dd_min variable
        ## If the TMOUT variable is set greater than 0, the time-out is set to
        ## $TMOUT seconds
        if [ ${TMOUT:--1} -ge 0 ]
        then
          _TMOUT=$TMOUT
          stty -echo -icanon time $(( $_TMOUT * 10 )) min ${dd_min:-1}
        else
          stty -echo -icanon min ${dd_min:-1}
        fi
    }

    ## Read a key from the keyboard, using dd with a block size (bs) of 1.
    ## A period is appended, or command substitution will swallow a newline
    _KEY=$(dd bs=1 count=1 2>/dev/null; echo .)
    _KEY=${_KEY%?}  ## Remove the period

    ## If a variable has been given on the command line, assign the result to it
    [ -n "$1" ] && eval "$1=\$_KEY" ;;
    [ -t 0 ] && stty "$_STTY"  ## reset terminal
    [ -n "$_KEY" ]  ## Succeed if a key has been entered (not timed out)
}

_getline()
{
    ## Check that the parameter given is a valid variable name
    case $2 in
        [!a-zA-Z_]* | *[!a-zA-Z0-9_]* ) die 2 "Invalid variable name: $2" ;;
        *) var=${2:-_GETLINE} ;;
    esac

    ## If the variable name is "password" do not turn on echoing
    [ -t 0 ] && [ "$2" != "password" ] && stty echo
    case ${BASH_VERSION%%.*} in
        [2-9]|[1-9][0-9])
                read ${TMOUT:+-t$TMOUT} -ep "$1: " -- $var
                ;;
        *) printf "%s: " "$1" >&2
           IFS= read -r $var
           ;;
   esac
   [ -t 0 ] && stty -echo  ## turn echoing back off
}

getline()
{
    _getline "$@" && printf "%s\n" "$_GETLINE"
}

press_any_key()
{
    printf "\r <PRESS ANY KEY> "     ## Display the message
    get_key                          ## Get the keystroke
    printf "\r                   \r" ## Erase the message
}

menu1()
{
    m1_items=$#  ## Number of commands (i.e., arguments)
    while :      ## Endless loop
    do
      printf "%s " "$menu"  ## Display menu
      get_key Q             ## Get user's choice
      case $Q in
          0|q|""|"$NL" )
                     printf "\n"; break ;;   ## Break out
          [1-$m1_items])                          ## Valid number
                     printf "\n"
                     ( eval "\$$Q" )              ## Execute command
                     case $pause_after in         ## Pause if set
                         *?) press_any_key
                             ;;
                     esac
                     ;;
          *) printf "\n\t\a%sInvalid entry: %s\n" "${progname:+$progname: }" "$Q"
             continue
             ;;
      esac

      [ -n "$_MENU1" ] && break  ## If set, exit after one successful selection
    done
}

arg()
{
    case $1 in
        "") printf "%s? " "$prompt" >&2  ## Prompt for input
            stty echo                    ## Display characters entered
            read arg < /dev/tty          ## Get user's input
            ;;
        *) arg="$*"   ## Use existing arguments
           units=     ## For use with the conversion script, Chapter 5
           ;;
    esac
}

# Some error messages
error_no_arg () { die "option ${1%%=*} does not take any arguments"; }
error_missing_arg () { die "option ${1%%=*} takes an argument"; }

die() {
    result=$1
    shift
    printf "%s\n" "$*" >&2
    exit $result
}

_show_date()
{
    oldIFS=$IFS    ## Save old value of IFS
    IFS=" -./"     ## Allow splitting on hyphen, period, slash and space
    set -- $*      ## Re-split arguments
    IFS=$oldIFS    ## Restore old IFS

    ## If there are less than 3 arguments, use today's date
    [ $# -ne 3 ] && {
        date_vars  ## Populate date variables (see the next function)
        _SHOW_DATE="$_DAY $MonthAbbrev $YEAR"
        return
    }
    case $DATE_FORMAT in
        dmy) _y=$3     ## day-month-year format
             _m=${2#0}
             _d=${1#0}
             ;;
        mdy) _y=$3     ## month-day-year format
             _m=${1#0}
             _d=${2#0}
             ;;
        *) _y=$1       ## most sensible format
           _m=${2#0}
           _d=${3#0}
           ;;
    esac

    ## Translate number of month into abbreviated name
    set Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    eval _m=\${$_m}
    _SHOW_DATE="$_d $_m $_y"
}

show_date()
{
    _show_date "$@" && printf "%s\n" "$_SHOW_DATE"
}

date_vars()
{
    eval $(date "$@" "+DATE=%Y-%m-%d
                      YEAR=%Y
                      MONTH=%m
                      DAY=%d
                      TIME=%H:%M:%S
                      HOUR=%H
                      MINUTE=%M
                      SECOND=%S
                      datestamp=%Y-%m-%d_%H.%M.%S
                      DayOfWeek=%a
                      DayOfYear=%j
                      DayNum=%w
                      MonthAbbrev=%b")

    ## Remove leading zeroes for use in arithmetic expressions
    _MONTH=${MONTH#0}
    _DAY=${DAY#0}
    _HOUR=${HOUR#0}
    _MINUTE=${MINUTE#0}
    _SECOND=${SECOND#0}


    ## Sometimes the variable, TODAY, is more appropriate in the context of a
    ## particular script, so it is created as a synonym for $DATE
    TODAY=$DATE

    export DATE YEAR MONTH DAY TODAY TIME HOUR MINUTE SECOND
    export datestamp MonthAbbrev DayOfWeek DayNum
}

is_num()
{
    case $1 in
        *[!0-9]*) return 5 ;;  ## Fail is any character is not a digit from 0 to 9
    esac
}

is_num() {
    case ${1#-} in
        -v) isnum_verbose=1
            shift
            ;;
        *) isnum_verbose=0 ;;
    esac
    case $1 in
        *[!0-9]*) case $isnum_verbose in
                    1) printf "Not a number: %s\n" $1 >&2 ;;
                  esac
                  return 5
                  ;;
    esac
}

_abbrev_num() {
    case ${#1} in
	1|2|3|4) _ABBREV_NUM=$1 ;;
	5|6) _ABBREV_NUM=$(( ($1 + 500) / 1000 ))K ;;
	7|8|9) _ABBREV_NUM=$(( ($1 + 500000) / 1000000 ))M ;;
	10|11|12) _ABBREV_NUM=$(( ($1 + 500000000) / 1000000000 ))G ;;
	*) _ABBREV_NUM="HUGE" ;;
    esac
}

abbrev_num()
{
    _abbrev_num "$@" && printf "%s\n" "$_ABBREV_NUM"
}

_commas() {
    _COMMAS=       ## Clear the variable for the result
    _DECPOINT=.    ## Character for decimal point; adjust for other locales
    _TH_SEP=,      ## Character for separator; adjust for other locales
    case $1 in
        "$_DECPOINT"*) _COMMAS=$1  ## Number begins with dot; no action needed
            return
            ;;
        *"$_DECPOINT")  ## Number ends with dot; store it in $c_decimal
            c_num=${1%"$_DECPOINT"}
            c_decimal=.
            ;;
        *"$_DECPOINT"*) c_num=${1%"$_DECPOINT"*} ## Separate integer and fraction
             c_decimal=$_DECPOINT${1#*"$_DECPOINT"}
             ;;
        *) c_num=$1      ## No dot, therefore no decimal
           c_decimal=
           ;;
    esac

    while :
    do
       case $c_num in
          ## Three, two or one digits [left] in $num;
          ## add them to the front of _COMMAS and exit from loop
          ???|??|?) _COMMAS=${c_num}${_COMMAS:+"$_TH_SEP"$_COMMAS}
                    break
                    ;;
          *) ## More than three numbers in $num
             left=${c_num%???}  ## All but the last three digits

             ## Prepend the last three digits and a comma
             _COMMAS=${c_num#${left}}${_COMMAS:+"$_TH_SEP"$_COMMAS}
             c_num=$left ## Remove last three digits
             ;;
       esac
    done

    ## Replace decimal fraction, if any
    _COMMAS=${_COMMAS}${c_decimal}
}

commas()
{
  for n
  do
     _commas "$n" && printf "%s\n" "$_COMMAS"
  done
}

pr1()
{
    case $1 in
        -w) pr_w= ;;
        *) pr_w=-.${COLUMNS:-80} ;;
    esac
    printf "%${pr_w}s\n" "$@"
}

checkdirs() {
  checkdirs=0   ## Return status: success unless a check fails
  for dir       ## Loop through the directory on the command line
  do
    [ -d "$dir" ] &&     ## Check for the directory
            continue ||  ## If it exists, proceed to the next one
     mkdir -p "$dir" ||  ## Attempt to create it
          checkdirs=1    ## Set error status if $dir couldn't be created
  done
  return $checkdirs      ## Return error status
}

checkfiles()
{
    checkdict=$1                     ## Directory must be first argument
    [ -d "$checkdict" ] || return 13 ## Fail if directory does not exist
    shift                            ## Remove dir from positional parameters
    for _CHECKFILE                   ## Loop through files on command line
    do
      [ -f "$checkdict/$checkfile" ] || return 5
    done
}

_zpad()
{
    _ZPAD=$1
    while [ ${#_ZPAD} -lt $2 ]
    do
        _ZPAD=${3:-0}$_ZPAD
    done
}

zpad()
{
    _zpad "$@" && printf "%s\n" "$_ZPAD"
}

_uniqfile()
{
    _base=$1
    _n=1
    _zpad $_n ${VERSION_WIDTH}
    _UNIQFILE=$_base-$_ZPAD
    while [ -f "$_UNIQFILE" ] || [ -d "$_UNIQFILE" ]
    do
      _zpad $_n ${VERSION_WIDTH}
      _UNIQFILE=$_base-$_ZPAD
      _n=$(( $_n + 1 ))
    done
}

cleanup()
{
   ## delete temporary directory and files
   [ -n "$tempfile_dir" ] && rm -rf "$tempfile_dir"

   ## Reset the terminal characteristics
   [ -t 0 ] && {
       [ -n "$_STTY" ] && stty $_STTY || stty sane
   }
   exit
}
trap cleanup EXIT  ## Set trap to call cleanup on exit