Finding duplicate blocks of text within a file using shell script

Question

Say I have a text file with the following lines:-

abcd/efgh/a.jar
{
abcd/efgh/a.class
cdef/ghij/b.class
klmn/opqr/c.class
}
lkmn/opqr/b.zip
{
abcd/efgh/a.class
cdef/ghij/b.class
}
abcd/efgh/a.jar
{
cdef/ghij/b.class
}

Now abcd/efgh/a.jar in the first case has abcd/efgh/a.class, cdef/ghij/b.class and klmn/opqr/c.class within the curly braces. Consider it as 1 block of text. Now abcd/efgh/a.jar below again has cdef/ghij/b.class within curly braces. I want to remove this section/block of text. So the final output needs to be like:-

abcd/efgh/a.jar
{
abcd/efgh/a.class
cdef/ghij/b.class
klmn/opqr/c.class
}
lkmn/opqr/b.zip
{
abcd/efgh/a.class
cdef/ghij/b.class
}

Any help would be highly appreciated :)

Answer 1

Use

for i in `awk '/}/ {if (NR!=1) print "";next} \
                {printf "%s ",$0,"}"}END{print ""}' yt.txt \
        |awk '{print $1}'|sort|uniq \
    `; \
    do \
        awk '/}/ {if (NR!=1) print "";next} \
            {printf "%s ",$0,"}"}END{printf ""} \
            ' yt.txt \
         |grep "$i"|sed 's/ /\n/g'|grep -v "$i"|sort|uniq \
            |awk -v var="$i" ' NR==1 {printf var} {print $0} END {print "}"}'  \
    ;done \

Same command in 1 line below (for copying purpose)

for i in `awk '/}/ {if (NR!=1) print "";next} {printf "%s ",$0,"}"}END{print ""}' yt.txt|awk '{print $1}'|sort|uniq` ; do awk '/}/ {if (NR!=1) print "";next} {printf "%s ",$0,"}"}END{printf ""}' yt.txt|grep "$i"|sed 's/ /\n/g'|grep -v "$i"|sort|uniq|awk -v var="$i" ' NR==1 {printf var} {print $0} END {print "}"}' ;done

Explanation:

The for part will return you the unique heading of the block (abcd/efgh/a.jar,lkmn/opqr/b.zip) and pass it to do block. The do part will first grep all the rows for each heading, which would include duplicates also. Then it will exclude the heading and merge all the remaining rows under that heading block, then add the heading at first row. And hardcode } at the end.

Example

bash-4.2$ cat yt.txt
abcd/efgh/a.jar
{
abcd/efgh/a.class
cdef/ghij/b.class
klmn/opqr/c.class
}
lkmn/opqr/b.zip
{
abcd/efgh/a.class
cdef/ghij/b.class
}
abcd/efgh/a.jar
{
cdef/ghij/b.class
d.class
}



bash-4.2$ for i in `awk '/}/ {if (NR!=1) print "";next} {printf "%s ",$0,"}"} \
> END{print ""}' yt.txt |awk '{print $1}'|sort|uniq` \
> ; do awk '/}/ {if (NR!=1) print "";next} {printf "%s ",$0,"}"}END{printf ""}' yt.txt \
>  |grep "$i"|sed 's/ /\n/g'|grep -v "$i"|sort|uniq \
> |awk -v var="$i" ' NR==1 {printf var} {print $0} END {print "}"}'\
> ;done
abcd/efgh/a.jar
{
abcd/efgh/a.class
cdef/ghij/b.class
d.class
klmn/opqr/c.class
}
lkmn/opqr/b.zip
{
abcd/efgh/a.class
cdef/ghij/b.class
}

Answer 2

After I saw the solution utilizing a for loop with awk and sort and uniq and grep and sed I tried a solution with one tool instead of six:

sed ':a
  N;$!ba
  y/\n_/_\n/;s/^/_/
  :b
  s/\(_[^_]*_{\)\([^}]*\)\(_[^_}]*\)\(_[^}]*\)\(_}.*\)\1\([^}]*\)\3_/\1\2\3\4\5\1\6_/;tb
  :c
  s/\(_[^_]*_{\)\([^}]*\)_}\(.*\)\1\([^}]*\)_}/\1\2\4_}\3/;tc
  s/^_//
  y/\n_/_\n/' yourfile

does the job, but I have to admit that the regular expressions are easiert to write than to read ... (-;

Answer 3

perl -alF'/\n[}{]\n/' -0777ne '
   for ( 0 .. $#F/2 ) {
      my $i = 2*$_;
      my($k,$v) = @F[$i,$i+1];
      if ( exists $h{$k} ) {
         $h{$k} .= join $\, grep { ! exists $seen{$k,$_} } split $\, $v;
      } else {
         push @k, $k;
         $seen{$k,$_}++ for split $\, $h{$k} = $v;
      }
   }
   print "$_\n{\n$h{$_}\n}" for @k;
' yourfile

---

Results

abcd/efgh/a.jar
{
abcd/efgh/a.class
cdef/ghij/b.class
klmn/opqr/c.class
}
lkmn/opqr/b.zip
{
abcd/efgh/a.class
cdef/ghij/b.class
}

---

Working

The input file is slurped and then split up into fields based on the field separator mentioned by the -F option. We will be getting even number of elements in the array @F. The even numbered then go in as the keys of the hash %h whilst their corresp. values are grabbed from the next odd value.

The hash %h is populated by splitting up the odd numbered elems on record separator ($\ = \n). At the same time we place the key into the array @k so that we can retrieve hash elements in order they were encountered.

All the while only those odd elements are used that are not already seen.