AWK: is there a way to check the next record for a number?

Question

I have data I am trying to manipulate. The only data we don't want to manipulate is the beginning and the end. The beginning is easy, as the beginning is always exon_1. The end is not always exon_12 or whatever, it varies.

My question is, does AWK have a way to store the next record without going on to the next record? The way I wanted to tackle this is to check if the next record is exon_1, and if it is then don't add +1 and +2 to the end of column 5

By the way, I am coding in a bash script. What else the script does is irrelevant to the question.

Code I have so far:

awk '{ if ($9~"exon_1;") {$3 = $3 FS "0"; $3 = $3 FS "0"; print $0 } else {$4 = $4-1 FS $4; $4 = $4-1 FS $4; print $0}}'  exons.gff3 > exons2.gff3
awk '{ {$7 = $7 FS $7+1; $7 = $7 FS $7+2; print $0}}'  exons2.gff3 > exons3.gff3

Code I'm thinking of but can't quiet implement:

awk '{ if ($9~"exon_1;") {$3 = $3 FS "0"; $3 = $3 FS "0"; print $0 } else {$4 = $4-1 FS $4; $4 = $4-1 FS $4; print $0}}'  exons.gff3 > exons2.gff3
awk 'BEGIN {NR+1 = a} { if (a's $11~"exon_1;") {$7 = $7 FS "0"; $7 = $7 FS "0"; print $0} {$7 = $7 FS $7+1; $7 = $7 FS $7+2; print $0}}'  exons2.gff3 > exons3.gff3

Input:

Chr1    MSU_osa1r7  exon    2903    3268    .   +   .   ID=LOC_Os01g01010.1:exon_1;Parent=LOC_Os01g01010.1
Chr1    MSU_osa1r7  exon    3354    3616    .   +   .   ID=LOC_Os01g01010.1:exon_2;Parent=LOC_Os01g01010.1
Chr1    MSU_osa1r7  exon    4357    4455    .   +   .   ID=LOC_Os01g01010.1:exon_3;Parent=LOC_Os01g01010.1
Chr1    MSU_osa1r7  exon    5457    5560    .   +   .   ID=LOC_Os01g01010.1:exon_4;Parent=LOC_Os01g01010.1
Chr1    MSU_osa1r7  exon    7136    7944    .   +   .   ID=LOC_Os01g01010.1:exon_5;Parent=LOC_Os01g01010.1
Chr1    MSU_osa1r7  exon    8028    8150    .   +   .   ID=LOC_Os01g01010.1:exon_6;Parent=LOC_Os01g01010.1
Chr1    MSU_osa1r7  exon    8232    8320    .   +   .   ID=LOC_Os01g01010.1:exon_7;Parent=LOC_Os01g01010.1
Chr1    MSU_osa1r7  exon    8408    8608    .   +   .   ID=LOC_Os01g01010.1:exon_8;Parent=LOC_Os01g01010.1
Chr1    MSU_osa1r7  exon    9210    9617    .   +   .   ID=LOC_Os01g01010.1:exon_9;Parent=LOC_Os01g01010.1
Chr1    MSU_osa1r7  exon    10104   10187   .   +   .   ID=LOC_Os01g01010.1:exon_10;Parent=LOC_Os01g01010.1
Chr1    MSU_osa1r7  exon    10274   10430   .   +   .   ID=LOC_Os01g01010.1:exon_11;Parent=LOC_Os01g01010.1
Chr1    MSU_osa1r7  exon    10504   10817   .   +   .   ID=LOC_Os01g01010.1:exon_12;Parent=LOC_Os01g01010.1
Chr1    MSU_osa1r7  exon    422527  422748  .   +   .   ID=LOC_Os01g01800.1:exon_1;Parent=LOC_Os01g01800.1
Chr1    MSU_osa1r7  exon    422910  422972  .   +   .   ID=LOC_Os01g01800.1:exon_2;Parent=LOC_Os01g01800.1
Chr1    MSU_osa1r7  exon    423069  423379  .   +   .   ID=LOC_Os01g01800.1:exon_3;Parent=LOC_Os01g01800.1
Chr1    MSU_osa1r7  exon    423524  423620  .   +   .   ID=LOC_Os01g01800.1:exon_4;Parent=LOC_Os01g01800.1
Chr1    MSU_osa1r7  exon    423697  423774  .   +   .   ID=LOC_Os01g01800.1:exon_5;Parent=LOC_Os01g01800.1
Chr1    MSU_osa1r7  exon    423871  423930  .   +   .   ID=LOC_Os01g01800.1:exon_6;Parent=LOC_Os01g01800.1

(Ignore that it changed to space delimited, I'll fix that later. I just copied what my code produces now and added what I wanted it to do to the last exon_.)

Output:

Chr1 MSU_osa1r7 exon 0 0 2903 3268 3269 3270 . + . ID=LOC_Os01g01010.1:exon_1;Parent=LOC_Os01g01010.1
Chr1 MSU_osa1r7 exon 3352 3353 3354 3616 3617 3618 . + . ID=LOC_Os01g01010.1:exon_2;Parent=LOC_Os01g01010.1
Chr1 MSU_osa1r7 exon 4355 4356 4357 4455 4456 4457 . + . ID=LOC_Os01g01010.1:exon_3;Parent=LOC_Os01g01010.1
Chr1 MSU_osa1r7 exon 5455 5456 5457 5560 5561 5562 . + . ID=LOC_Os01g01010.1:exon_4;Parent=LOC_Os01g01010.1
Chr1 MSU_osa1r7 exon 7134 7135 7136 7944 7945 7946 . + . ID=LOC_Os01g01010.1:exon_5;Parent=LOC_Os01g01010.1
Chr1 MSU_osa1r7 exon 8026 8027 8028 8150 8151 8152 . + . ID=LOC_Os01g01010.1:exon_6;Parent=LOC_Os01g01010.1
Chr1 MSU_osa1r7 exon 8230 8231 8232 8320 8321 8322 . + . ID=LOC_Os01g01010.1:exon_7;Parent=LOC_Os01g01010.1
Chr1 MSU_osa1r7 exon 8406 8407 8408 8608 8609 8610 . + . ID=LOC_Os01g01010.1:exon_8;Parent=LOC_Os01g01010.1
Chr1 MSU_osa1r7 exon 9208 9209 9210 9617 9618 9619 . + . ID=LOC_Os01g01010.1:exon_9;Parent=LOC_Os01g01010.1
Chr1 MSU_osa1r7 exon 10102 10103 10104 10187 10188 10189 . + . ID=LOC_Os01g01010.1:exon_10;Parent=LOC_Os01g01010.1
Chr1 MSU_osa1r7 exon 10272 10273 10274 10430 10431 10432 . + . ID=LOC_Os01g01010.1:exon_11;Parent=LOC_Os01g01010.1
Chr1 MSU_osa1r7 exon 10502 10503 10504 10817 0 0 . + . ID=LOC_Os01g01010.1:exon_12;Parent=LOC_Os01g01010.1
Chr1 MSU_osa1r7 exon 0 0 2984 3255 3256 3257 . + . ID=LOC_Os01g01010.2:exon_1;Parent=LOC_Os01g01010.2
Chr1 MSU_osa1r7 exon 3352 3353 3354 3616 3617 3618 . + . ID=LOC_Os01g01010.2:exon_2;Parent=LOC_Os01g01010.2
Chr1 MSU_osa1r7 exon 4355 4356 4357 4455 4456 4457 . + . ID=LOC_Os01g01010.2:exon_3;Parent=LOC_Os01g01010.2
Chr1 MSU_osa1r7 exon 5455 5456 5457 5560 5561 5562 . + . ID=LOC_Os01g01010.2:exon_4;Parent=LOC_Os01g01010.2
Chr1 MSU_osa1r7 exon 7134 7135 7136 7944 7945 7946 . + . ID=LOC_Os01g01010.2:exon_5;Parent=LOC_Os01g01010.2
Chr1 MSU_osa1r7 exon 8026 8027 8028 8150 0 0 . + . ID=LOC_Os01g01010.2:exon_6;Parent=LOC_Os01g01010.2

What you're seeing is that the last exon_ does not have a +1 and +2 value added next to it, I want the last value to not change.

Answer 1

Awk does not look ahead, but you can always create a variable which stores the previous record and arrange to write that rather than the current record. The END section would tidy up.