I have a file which has many lines, each consisting of a comma-separated list. I'd like to sort each of these lines.
If I had a single line, it would be easy:
<file tr ',' '\n' | sort | tr '\n' ','
But if I do this on my file it lumps together all the lines which I don't want. How do I restrict this?
It is (fairly) easy in Perl:
#!/usr/bin/env perl
use strict;
use warnings;
$, = ",";
while (<>)
{
chomp;
my @fields = split /,/;
my @sorted = sort(@fields);
$sorted[scalar(@sorted)-1] .= "\n";
print @sorted;
}
The trickiness involves saving the sorted array so that the newline can be added to the last element of the array, so that you don't get lines ending with a comma. If that doesn't matter, then it is more compact — replace the last three lines of the loop with:
print sort(@fields), "\n";
x,b,z,a,c,e,f,g,d
3,19,12,17,16,19,18,17,20,16
a,b,c,d,e,f,g,x,z
12,16,16,17,17,18,19,19,20,3
It being Perl, there are ways to compress it:
perl -l -p -a -F, -e '$_ = join(",", sort(@F))'
That's:
-l autochomp and handle newlines.-p automatically read each input line, process it with the script, and print after each line.-a split input lines into array F based on field separator.-F, the field separator is a comma.-e is followed by the program.$_, to the comma-joined list of sorted values in array F.Perl handles the rest.