Shell Programming and Scripting

I am definitely not an expert with awk, and I want to reformat a text file like the following. This is probably a very easy one for an expert out there. I would like to keep the lines in the same order, but move the heading to only be listed once above the lines.

This is what the text file looks like....

APPLE: This line should be first
APPLE: this line could, but should be second
APPLE: this should be last
BANANA: First
BANANA: Second
BANANA: third
BANANA: fourth
BANANA: fifth
COOKIE: 1
COOKIE: 2
COOKIE: 3
DOG: 1
DOG: 2
DOG: 3
DOG: 4

I would like to reformat this to say:

APPLE:
This line should be first
this line could, but should be second
this should be last

BANANA:
First
Second
third
fourth
fifth

COOKIE:
1
2
3

DOG:
1
2
3
4


Thanks in advance!

Code:

awk '{if(++a[$1]==1){sub(" ","\n");print "\n"$0}else{sub($1" ","");print}}' file

Thanks!! You're the man/woman!

Here is another way of doing it:

Code:

#!/bin/ksh
IFS=':'
mPrev=""
while read mTitle mDesc
do
  if [[ "${mTitle}" != "${mPrev}" ]]; then
    echo ${mTitle}':'
    mPrev=${mTitle}
  fi
  echo ${mDesc}
done < inp_file

@yinyuemi
can you please explain me the code in detail plzz....

Code:

$ ruby -e 'BEGIN{h={}};File.open("file").each{|x|a,b=x.split(/\s+/,2);(h[a]||= [])<<b};END{h.each{|k,v| puts k;v.each{|y|puts y }}}'
APPLE:
This line should be first
this line could, but should be second
this should be last
BANANA:
First
Second
third
fourth
fifth
COOKIE:
1
2
3
DOG:
1
2
3
4