uniq sort parsing - shell

Question

I have one file with field separated by ";", like this:
test;group;10.10.10.10;action2
test2;group;10.10.13.11;action1
test3;group3;10.10.10.10;action3
tes4;group;10.10.10.10;action4
test5;group2;10.10.10.12;action5
test6;group4;10.10.13.11;action8
I would like to identify all non-unique IP addresses (3rd column). With the example the extract should be:
test;group;10.10.10.10;action2
test3;group3;10.10.10.10;action3
tes4;group;10.10.10.10;action4
test2;group;10.10.13.11;action1
test6;group4;10.10.13.11;action8
Sorted by IP address (3rd column).
Ssing simple commands like cat, uniq, sort, awk (not Perl, not Python, only shell).
Any idea?

Answer 1

$ awk -F';' 'NR==FNR{a[$3]++;next}a[$3]>1' file file|sort -t";" -k3
test;group;10.10.10.10;action2
test3;group3;10.10.10.10;action3
tes4;group;10.10.10.10;action4
test2;group;10.10.13.11;action1
test6;group4;10.10.13.11;action8
awk picks all duplicated ($3) lines
sort sorts by ip

Answer 2

You can also try this solution using grep, cut, sort, uniq, and a casual process substitution in the middle.
grep -f <(cut -d ';' -f3 file | sort | uniq -d) file | sort -t ';' -k3
It is not really elegant (I actually prefer the awk answer given above), but I think worth sharing, since it accomplishes what you want.

Answer 3

here is another awk assisted pipeline
$ awk -F';' '{print $0 "\t" $3}' file | sort -sk2 | uniq -Df1 | cut -f1
test;group;10.10.10.10;action2
test3;group3;10.10.10.10;action3
tes4;group;10.10.10.10;action4
test2;group;10.10.13.11;action1
test6;group4;10.10.13.11;action8
single pass, so special caching; also keeps the original order (stable sorting). Assumes tab doesn't appear in the fields.

Answer 4

This is very similar to Kent's answer, but with a single pass through the file. The tradeoff is memory: you need to store the lines to keep. This uses GNU awk for the PROCINFO variable.
awk -F';' '
{count[$3]++; lines[$3] = lines[$3] $0 ORS}
END {
PROCINFO["sorted_in"] = "#ind_str_asc"
for (key in count)
if (count[key] > 1)
printf "%s", lines[key]
}
' file
The equivalent perl
perl -F';' -lane '
$count{$F[2]}++; push #{$lines{$F[2]}}, $_
} END {
print join $/, #{$lines{$_}}
for sort grep {$count{$_} > 1} keys %count
' file

Answer 5

awk + sort + uniq + cut:
$ awk -F ';' '{print $0,$3}' <file> | sort -k2 | uniq -D -f1 | cut -d' ' -f1
sort + awk
$ sort -t';' -k3,3 | awk -F ';' '($3==k){c++;b=b"\n"$0}($3!=k){if (c>1) print b;c=1;k=$3;b=$0}END{if(c>1)print b}
awk
$ awk -F ';' '{b[$3"_"++k[$3]]=$0; }
END{for (i in k) if(k[i]>1) for(j=1;j<=k[i];j++) print b[i"_"j] } <file>
This buffers the full file (same as sort does) and keeps track how many times a key k is appearing. At the end, if the key appears more then ones, print the full set.
test2;group;10.10.13.11;action1
test6;group4;10.10.13.11;action8
test;group;10.10.10.10;action2
test3;group3;10.10.10.10;action3
tes4;group;10.10.10.10;action4
If you want it sorted :
$ awk -F ';' '{b[$3"_"++k[$3]]=$0; }
END{ asorti(k,l);
for (i in l) if(k[l[i]]>1) for(j=1;j<=k[l[i]];j++) print b[l[i]"_"j] } <file>