Ubuntu – Print the first column

The first one-liner / full script parse and convert the file format described in the question; the second full script parses and converts a FASTA file format.

#1

Golfed one-liner:

perl -lane 'my $s;my @m=$F[1]=~/C.?/g;foreach(@m){$_ eq"CC"?$s.="C":$s.="C#"}push(@F,$s);print(join(",",@F))' infile

Expanded full script:

#!/usr/bin/perl

use strict;
use warnings;

@ARGV == 1 || die("Usage: <command> <input_file>\n");

open(my $in, $ARGV[0]) || die("Could not open input file \"$ARGV[0]\": $!\n");

while(<$in>) {
    my $string;
    my @fields = split(" ");
    my @matches = $fields[1] =~ /C.?/g;
    foreach(@matches) {
        $_ eq "CC" ? $string .= "C" : $string .= "C#"
    }
    push(@fields, $string);
    print(join(",", @fields) . "\n")
}

close($in);

exit

Explanation:

• The input file is processed line by line;
• Each line is splitted into two strings, the part before the space and the part after the space;
• Each substring made of a "C" character optionally followed by another character (optionally to catch also a "C" character at the end of the string) in the second string is evaluated, and if the character following the "C" is a "C", "C" is appended to the end of a custom temporary string; otherwise "C#" is appended at the end of the custom temporary string;
• The first, second and custom temporary string are printed, comma-separated, followed by a newline;

Sample output:

% cat infile
c32_g1_i1_3 GQKAKLKVPVFFLHRRGSICSSFYLMFSFEIKKK*TSKN*CFVCVRVRNRERAGVKCAHVYCPMFNGTQTH*IIISSLNS
c32_g1_i1_6 AV*TADDDLVRLCSIEHGTIHMCTLYTCCTLTVTHTYTHKTLIFACLFFFNFKGEHQIERAANRTSSM*KKHRNF*LGLLAX
% perl -ne 'my $s;my @f=split(" ");my @m=$f[1]=~/C.?/g;foreach(@m){$_ eq"CC"?$s.="C":$s.="C#"}push(@f,$s);print(join(",",@f)."\n")' infile
c32_g1_i1_3,GQKAKLKVPVFFLHRRGSICSSFYLMFSFEIKKK*TSKN*CFVCVRVRNRERAGVKCAHVYCPMFNGTQTH*IIISSLNS,C#C#C#C#C#
c32_g1_i1_6,AV*TADDDLVRLCSIEHGTIHMCTLYTCCTLTVTHTYTHKTLIFACLFFFNFKGEHQIERAANRTSSM*KKHRNF*LGLLAX,C#C#CC#C#

#2

Expanded full version:

#!/usr/bin/perl

use strict;
use warnings;

@ARGV == 1 || die("Usage: <command> <input_file>\n");

open(my $in, $ARGV[0]) || die("Could not open input file \"$ARGV[0]\": $!\n");
open(my $tmp, "+>", "tmpfile") || die("Could not create temporary file \"tmpfile\": $!\n");

select($tmp);

while(<$in>) {
    if(/^>/) {
        s/$/ /
    }
    if(my $next = <$in>) {
        if($next !~ /^>/) {
            chomp
        }
        print;
        seek($in, -length($next), 1)
    }
    else {
        print
    }
}

close($in);

seek($tmp, 0, 0);

select(STDOUT);

while(<$tmp>) {
    my $string;
    my @fields = split(/ (?!.* )|\n/);
    my @matches = $fields[1] =~ /C.?/g;
    foreach(@matches) {
        $_ eq "CC" ? $string .= "C" : $string .= "C#"
    }
    push(@fields, $string);
    print(join(",", @fields) . "\n")
}

close($tmp);

unlink("tmpfile");

exit

Explanation:

• The input file is processed line by line;
• If the current line starts with a > character, a space is appended to the line; if a following line exists and doesn't start with a > character, the newline character is stripped from the current line; the current line is printed to a temporary file;
• The temporary file is processed line by line;
• Each line is splitted into two strings, the part before the last space and the part after the last space;
• Each substring made of a "C" character optionally followed by another character (optionally to catch also a "C" character at the end of the string) in the second string is evaluated, and if the character following the "C" is a "C", "C" is appended to the end of a custom temporary string; otherwise "C#" is appended at the end of the custom temporary string;
• The first, second and custom temporary string are printed, comma-separated, followed by a newline;
• The temporary file is removed;

Sample output:

% cat infile 
>c32_g1_i1_
3GQKAKLKVPVFFLHRRGSICSSFYLMFSFEIKKK*TSKN*CFVCVRVRNRERAGVKCAHVYCPMFNGTQTH*IIISSLNS
3GQKAKLKVPVFFLHRRGSICSSFYLMFSFEIKKK*TSKN*CFVCVRVRNRERAGVKCAHVYCPMFNGTQTH*IIISSLNS
>c32_g1_i1_
6AV*TADDDLVRLCSIEHGTIHMCTLYTCCTLTVTHTYTHKTLIFACLFFFNFKGEHQIERAANRTSSM*KKHRNF*LGLLAX
6AV*TADDDLVRLCSIEHGTIHMCTLYTCCTLTVTHTYTHKTLIFACLFFFNFKGEHQIERAANRTSSM*KKHRNF*LGLLAX
% perl script.pl infile 
>c32_g1_i1_,3GQKAKLKVPVFFLHRRGSICSSFYLMFSFEIKKK*TSKN*CFVCVRVRNRERAGVKCAHVYCPMFNGTQTH*IIISSLNS3GQKAKLKVPVFFLHRRGSICSSFYLMFSFEIKKK*TSKN*CFVCVRVRNRERAGVKCAHVYCPMFNGTQTH*IIISSLNS,C#C#C#C#C#C#C#C#C#C#
>c32_g1_i1_,6AV*TADDDLVRLCSIEHGTIHMCTLYTCCTLTVTHTYTHKTLIFACLFFFNFKGEHQIERAANRTSSM*KKHRNF*LGLLAX6AV*TADDDLVRLCSIEHGTIHMCTLYTCCTLTVTHTYTHKTLIFACLFFFNFKGEHQIERAANRTSSM*KKHRNF*LGLLAX,C#C#CC#C#C#C#CC#C#

Can be achieved easily with awk as follows:

awk 'NR==FNR{inFileA[$1]; next} ($1 in inFileA)' fileA fileB > write_to_fileC

result,

seg1       one
seg2       two
seg3       three

at above, first we are reading the fileA and holds the entire column1 from into an array named inFileA, then look in fileB for its first column and if it's matched with the saved column1 from fileA then goes to print entire row of fileB.