How to grep a string in until loop in bash? -

i work on script compressing files. want 'until loop' til' content of variable matches pattern. script using zenity. major part:

part="0" pattern="^([0-9]{1}[0-9]*([km])$" until `grep -e "$pattern" "$part"` ;     part=$(zenity --entry \     --title="zip file" \     --text "choose size of divided parts: (0 = no division, *m = *mb, *k = *kb)" \     --entry-text "0");      if grep -e "$pattern" "$part" ;         zenity --warning --text "wrong text entry, try again." --no-cancel;     fi done 

i want accept string containing digits ended 'k' or 'm' (but not both of them) , don't accept string started '0'.

is pattern ok?

$ grep -w '^[1-9][0-9]*[km]$' <<< 45k 45k $ grep -w '^[1-9][0-9]*[km]$' <<< 001023m $ grep -w '^[1-9][0-9]*[km]$' <<< 1023m 1023m 

don't forget <<< in expression, you're not grep'ing file, string. more posix-compliant, can use:

echo 1023m | grep -w '^[1-9][0-9]*[km]$' 

but kinda ugly.

edit:

longer example:

initmessage="choose size of divided parts:\n(0 = no division, *m = *mb, *k = *kb)" errmessage="wrong input. please re-read following:\n\n$initmessage"  message="$initmessage"  while true ;     part=$(zenity --entry \          --title="zip file" \          --text "$message")     if grep -qw '^[1-9][0-9]*[km]$' <<< "$part" ;          zenity --info --text 'thank !'          break     else         message="$errmessage"     fi done 

also, not directly related question, may want have @ yad, same things zenity does, has more options. used lot when had write bash scripts, , found more useful zenity.