shellchooser.sh

#!/bin/sh
#!/bin/sh -e
# The -e option for /bin/sh (dash) at the she-bang,
# makes this process immediately exit
# if some condition fails, see `man sh`.

evil_eval_check=$( set | grep '^shells_.*=' | cut -f 1 -d '=' )
if test "x" != "x${evil_eval_check}"
        then
                echo 'Been injected with a posion.'
                exit 0
fi
i=0
i=$(( i + 1 ))
eval "shells_${i}=byobu"
i=$(( i + 1 ))
eval "shells_${i}=bash"
i=$(( i + 1 ))
eval "shells_${i}=bash\ +o\ history"
eval "shells_${i}_desc=bash\ without\ history"
default_choice=2
timeout_milliseconds=15
j=0
printf "\n"'Choose one of the following shells:'"\n"
while true
        do
                j=$(( j + 1 ))
                if test "x" != "x"$( ( eval 'echo "${shells_'${j}'_desc+y}"' ) )
                        then
                                desc=\$shells_${j}_desc
                else
                                desc=\$shells_${j}
                fi
                eval "echo ' - '$j') '$desc'.'"
                test "$j" -lt "$i" || break
done
echo ' - ''q'') ''exit without changes''(default).'
echo -n 'Press the identifier of your choice: '
#chosen_shell=$( while ! head -c 1 ; do true ; done )
# http://stackoverflow.com/a/32270158/165330 .
readchr () {
        old_stty_cfg=$( stty -g )
        stty -echo raw min 0 time ${timeout_milliseconds}
        printf '%s' $(dd bs=1 count=1 2>/dev/null)
        stty $old_stty_cfg
}
chosen_shell=$( readchr )
if [ "x" = "x$chosen_shell" ]
        then
                #echo 'setting default choice('$chosen_shell').'
                chosen_shell=$default_choice
fi
if test "1" != "$chosen_shell" && test "2" != "$chosen_shell" && test "3" != "$chosen_shell"
        then
                exit 1
fi
eval "shell_choice=\$shells_${chosen_shell}"
if command -v wmctrl >/dev/null 2>&1 && test "byobu" = "$shell_choice"
        then
                $( wmctrl -r :ACTIVE: -b add,maximized_vert,maximized_horz )
fi
if test "bash" = "$shell_choice"
        then
                $( wmctrl -r :ACTIVE: -b add,maximized_vert,maximized_horz )
                clear
fi
exec $shell_choice

stefanjonker at MexBook in ~/Desktop/script
$ bash -vx ./shellchooser.sh

!/bin/sh -e

The -e option for /bin/sh at the she-bang,

makes this process immediately exit

if some condition fails, see man sh.

evil_eval_check=$( set | grep '^shells_.=' | cut -f 1 -d '=' )
set | grep '^shells.=' | cut -f 1 -d '='
++ set
++ grep '^shells.*='
++ cut -f 1 -d =

• evil_eval_check=
  if test "x" != "x${evil_eval_check}"
  then
  echo 'Been injected with a posion.'
  exit 0
  fi
• test x '!=' x
  i=0
• i=0
  i=$(( i + 1 ))
• i=1
  eval "shells_${i}=byobu"
• eval shells_1=byobu
  shells_1=byobu
  ++ shells_1=byobu
  i=$(( i + 1 ))
• i=2
  eval "shells_${i}=bash"
• eval shells_2=bash
  shells_2=bash
  ++ shells_2=bash
  i=$(( i + 1 ))
• i=3
  eval "shells_${i}=bash\ +o\ history"
• eval 'shells_3=bash\ +o\ history'
  shells_3=bash\ +o\ history
  ++ shells_3='bash +o history'
  eval "shells_${i}_desc=bash\ without\ history"
• eval 'shells_3_desc=bash\ without\ history'
  shells_3_desc=bash\ without\ history
  ++ shells_3_desc='bash without history'
  default_choice=2
• default_choice=2
  timeout_milliseconds=15
• timeout_milliseconds=15
  j=0
• j=0
  printf "\n"'Choose one of the following shells:'"\n"
• printf '\nChoose one of the following shells:\n'

Choose one of the following shells:
while true
do
j=$(( j + 1 ))
if test "x" != "x"$( ( eval 'echo "${shells_'${j}'desc+y}"' ) )
then
desc=$shells${j}desc
else
desc=$shells${j}
fi
eval "echo ' - '$j') '$desc'.'"
test "$j" -lt "$i" || break
done

• true
• j=1
  ( eval 'echo "${shells_'${j}'_desc+y}"' )
  ++ eval 'echo "${shells_1_desc+y}"'
  echo "${shells_1_desc+y}"
  +++ echo ''
• test x '!=' x
• desc='$shells_1'
• eval 'echo ''' - '''1''') '''$shells_1'''.''''
  echo ' - '1') '$shells_1'.'
  ++ echo ' - 1) byobu.'
  • 1. byobu.
• test 1 -lt 3
• true
• j=2
  ( eval 'echo "${shells_'${j}'_desc+y}"' )
  ++ eval 'echo "${shells_2_desc+y}"'
  echo "${shells_2_desc+y}"
  +++ echo ''
• test x '!=' x
• desc='$shells_2'
• eval 'echo ''' - '''2''') '''$shells_2'''.''''
  echo ' - '2') '$shells_2'.'
  ++ echo ' - 2) bash.'
  • 2. bash.
• test 2 -lt 3
• true
• j=3
  ( eval 'echo "${shells_'${j}'_desc+y}"' )
  ++ eval 'echo "${shells_3_desc+y}"'
  echo "${shells_3_desc+y}"
  +++ echo y
• test x '!=' xy
• desc='$shells_3_desc'
• eval 'echo ''' - '''3''') '''$shells_3_desc'''.''''
  echo ' - '3') '$shells_3_desc'.'
  ++ echo ' - 3) bash' without history.
  • 3. bash without history.
• test 3 -lt 3
• break
  echo ' - ''q'') ''exit without changes''(default).'
• echo ' - q) exit without changes(default).'
  • q) exit without changes(default).
    echo -n 'Press the identifier of your choice: '
• echo -n 'Press the identifier of your choice: '
  Press the identifier of your choice: #chosen_shell=$( while ! head -c 1 ; do true ; done )

  http://stackoverflow.com/a/32270158/165330 .

  readchr () {
  old_stty_cfg=$( stty -g )
  stty -echo raw min 0 time ${timeout_milliseconds}
  printf '%s' $(dd bs=1 count=1 2>/dev/null)
  stty $old_stty_cfg
  }
  chosen_shell=$( readchr )
  readchr
  ++ readchr
  stty -g
  +++ stty -g
  ++ old_stty_cfg=gfmt1:cflag=4b00:iflag=6b02:lflag=200005cb:oflag=3:discard=f:dsusp=19:eof=4:eol=ff:eol2=ff:erase=7f:intr=3:kill=15:lnext=16:min=1:quit=1c:reprint=12:start=11:status=14:stop=13:susp=1a:time=0:werase=17:ispeed=9600:ospeed=9600
  ++ stty -echo raw min 0 time 15
  dd bs=1 count=1 2>/dev/null
  +++ dd bs=1 count=1
  ++ printf %s
  ++ stty gfmt1:cflag=4b00:iflag=6b02:lflag=200005cb:oflag=3:discard=f:dsusp=19:eof=4:eol=ff:eol2=ff:erase=7f:intr=3:kill=15:lnext=16:min=1:quit=1c:reprint=12:start=11:status=14:stop=13:susp=1a:time=0:werase=17:ispeed=9600:ospeed=9600
  + chosen_shell=
  if [ "x" = "x$chosen_shell" ]
  then
  #echo 'setting default choice('$chosen_shell').'
  chosen_shell=$default_choice
  fi
• '[' x = x ']'
• chosen_shell=2
  if test "1" != "$chosen_shell" && test "2" != "$chosen_shell" && test "3" != "$chosen_shell"
  then
  exit 1
  fi
• test 1 '!=' 2
• test 2 '!=' 2
  eval "shell_choice=$shells_${chosen_shell}"
• eval 'shell_choice=$shells_2'
  shell_choice=$shells_2
  ++ shell_choice=bash
  if command -v wmctrl >/dev/null 2>&1 && test "byobu" = "$shell_choice"
  then
  $( wmctrl -r :ACTIVE: -b add,maximized_vert,maximized_horz )
  fi
• command -v wmctrl
• test byobu = bash
  if test "bash" = "$shell_choice"
  then
  $( wmctrl -r :ACTIVE: -b add,maximized_vert,maximized_horz )
  clear
  fi
• test bash = bash
  wmctrl -r :ACTIVE: -b add,maximized_vert,maximized_horz
  ++ wmctrl -r :ACTIVE: -b add,maximized_vert,maximized_horz
• clear

exec $shell_choice

• exec bash
  bash-3.2$

thnX :)

de output zonder -vx is wel een stukkie fraaier ..
En ik ben ook benieuwd naar de output vanuit een andere shell omgeving dan bash .