Merge branch 't/arithmetic_eval'

Cooking for almost a month.

* t/arithmetic_eval:
  Use modern style arithmetic evaluation everwhere.

diff --combined common
index a7c39b11ae9f08f528fee3769665a50cbbb5151f,6b87c440afc9ec44e3d9231c7267eeeb914406d3..eaa5751b43a9133fba3e497b5d45babe1e46b0e9
--- 1/common
--- 2/common
+++ b/common
@@@ -35,7 -35,7 +35,7 @@@ EO
  gsu_is_a_number()
  {
        result="$1"
-       if test "$1" -eq "$1" &> /dev/null; then
+       if (("$1" == "$1")) &> /dev/null; then
                ret=$GSU_SUCCESS
        else
                ret=-$E_GSU_NOT_A_NUMBER
@@@ -49,12 -49,12 +49,12 @@@ gsu_short_msg(
  
  gsu_msg()
  {
 -      gsu_short_msg "$_gsu_self: $1"
 +      gsu_short_msg "$gsu_name: $1"
  }
  
  gsu_date_msg()
  {
 -      gsu_short_msg "$_gsu_self $(date): $1"
 +      gsu_short_msg "$gsu_name $(date): $1"
  }
  
  gsu_err_msg()
@@@ -62,11 -62,11 +62,11 @@@
        local txt="$result" err
  
        gsu_is_a_number "$ret"
-       if test $ret -lt 0; then
+       if (($ret < 0)); then
                gsu_msg "unknown error ($ret:$txt)"
                exit 1
        fi
-       if test $result -ge 0; then
+       if (($result >= 0)); then
                gsu_msg "unknown error ($result:$txt)"
                exit 1
        fi
@@@ -81,7 -81,8 +81,7 @@@
  
  _gsu_setup()
  {
 -      _gsu_self="$(basename $0)"
 -      gsu_name="${gsu_name:=$_gsu_self}"
 +      gsu_name="${gsu_name:-${0##*/}}"
        gsu_config_var_prefix="${gsu_config_var_prefix:=$gsu_name}"
        gsu_banner_txt="${gsu_banner_txt:-set \$gsu_banner_txt to customize this message}"
        _gsu_init_errors

diff --combined subcommand
index 6449d6efffaeba565b25c905f34f39eb9ae07db0,77c7d62882f1f61a1544d383a81b27f6e2e8da31..05860f68395f67ffd3e9a51a60e48eb857a9cca8
--- 1/subcommand
--- 2/subcommand
+++ b/subcommand
@@@ -8,7 -8,7 +8,7 @@@ f
  
  _gsu_usage()
  {
 -      gsu_short_msg "# Usage: $_gsu_self command [options]"
 +      gsu_short_msg "# Usage: $gsu_name command [options]"
  }
  
  # Return an extended regular expression to match against $0.
@@@ -110,11 -110,11 +110,11 @@@ _com_prefs(
                ret=-$E_GSU_MKDIR
                result="${conf%/*}"
                mkdir -p "$result"
-               [[ $? -ne 0 ]] && return
+               (($? != 0)) && return
                ret=-$E_GSU_EDITOR
                result="${EDITOR:-vi}"
                "$result" "$conf"
-               [[ $? -ne 0 ]] && return
+               (($? != 0)) && return
                ret=$GSU_SUCCESS
                return
        fi
@@@ -160,15 -160,15 +160,15 @@@ _com_man(
        local minus_signs="--------------------------------------------------"
          local com num
  
 -      echo "$_gsu_self (_${gsu_banner_txt}_) manual"
 -      echo "${equal_signs:0:${#_gsu_self} + ${#gsu_banner_txt} + 16}"
 +      echo "$gsu_name (_${gsu_banner_txt}_) manual"
 +      echo "${equal_signs:0:${#gsu_name} + ${#gsu_banner_txt} + 16}"
        echo
  
          sed -e '1,/^#\{70,\}/d' -e '/^#\{70,\}/,$d' $0 -e 's/^# *//'
        echo "----"
          echo
 -      echo "$_gsu_self usage"
 -      echo "${minus_signs:0:${#_gsu_self} + 6}"
 +      echo "$gsu_name usage"
 +      echo "${minus_signs:0:${#gsu_name} + 6}"
        printf "\t"
        _gsu_usage 2>&1
        echo "Each command has its own set of options as described below."
@@@ -180,9 -180,7 +180,7 @@@
        _gsu_available_commands
          for com in $result; do
                num=${#com}
-               if test $num -lt 4; then
-                       num=4
-               fi
+               (($num < 4)) && num=4
                  echo "${minus_signs:0:$num}"
                  echo "$com"
                  echo "${minus_signs:0:$num}"
@@@ -222,7 -220,7 +220,7 @@@ _com_help(
        ere="$result"
  
        if (($# == 0)); then
 -              gsu_short_msg "### $_gsu_self -- $gsu_banner_txt ###"
 +              gsu_short_msg "### $gsu_name -- $gsu_banner_txt ###"
                _gsu_usage 2>&1
                {
                        printf "com_help()\n$gsu_help_txt" | head -n 4; echo "--"
@@@ -252,7 -250,7 +250,7 @@@
                                # and print the sucker
                                p'
                echo
 -              echo "# Try $_gsu_self help <command> for info on <command>."
 +              echo "# Try $gsu_name help <command> for info on <command>."
                ret=$GSU_SUCCESS
                return
        fi
@@@ -332,7 -330,7 +330,7 @@@ gsu_getopts(
  '
  
        gsu_check_arg_count $# 1 1
-       if [[ $ret -lt 0 ]]; then
+       if (($ret < 0)); then
                gsu_err_msg
                exit 1
        fi
@@@ -529,7 -527,7 +527,7 @@@ gsu(
        _gsu_setup
        _gsu_available_commands
        gsu_cmds="$result"
-       if test $# -eq 0; then
+       if (($# == 0)); then
                _gsu_usage
                _gsu_print_available_commands
                exit 1
@@@ -539,7 -537,7 +537,7 @@@
        # check internal commands
        if [[ "$arg" = "help" || "$arg" = "man" || "$arg" = "prefs" || "$arg" = "complete" ]]; then
                _com_$arg "$@"
-               if [[ "$ret" -lt 0 ]]; then
+               if (("$ret" < 0)); then
                        gsu_err_msg
                        exit 1
                fi
@@@ -550,7 -548,7 +548,7 @@@
        for i in $gsu_cmds; do
                if test "$arg" = "$i"; then
                        com_$arg "$@"
-                       if [[ "$ret" -lt 0 ]]; then
+                       if (("$ret" < 0)); then
                                gsu_err_msg
                                exit 1
                        fi
@@@ -581,16 -579,16 +579,16 @@@
  gsu_check_arg_count()
  {
        ret=-$E_GSU_BAD_ARG_COUNT
-       if [[ $# -eq 2 ]]; then # only num1 is given
+       if (($# == 2)); then # only num1 is given
                result="at least $2 args required, $1 given"
-               [[ $1 -lt $2 ]] && return
+               (($1 < $2)) && return
                ret=$GSU_SUCCESS
                return
        fi
        # num1 and num2 given
        result="need at least $2 args, $1 given"
-       [[ $1 -lt $2 ]] && return
+       (($1 < $2)) && return
        result="need at most $3 args, $1 given"
-       [[ $1 -gt $3 ]] && return
+       (($1 > $3)) && return
        ret=$GSU_SUCCESS
  }