Addition of characters to column in tab file
 

Guys, I have a tab delimited file. Multiple columns.
Need to add the characters chr to the 3rd column which already has a 2 digit number there.

Is there a command line that I can use to add in the characters 'chr' in front of the digits in every row in the 3rd column?

Thanks,
Julian

It would help to see a few before and after example rows, but its definitely do-able.

Here's what I want to do. Before: (First 5 lines of 70+ million lines)
SRR036740.6 WICMT-SOLEXA2_FC20A5VAAXX:4:1:880:684 length=26 + 2 115333875 TTACAATAAGGAGAAAGGTGCATCTG IIIIIIIIIIIIIIIIIIIIIIIIII
SRR036740.1 WICMT-SOLEXA2_FC20A5VAAXX:4:1:875:740 length=26 + 2 166030789 TATCGAGTCTCTTTTCAAAGCATTCA IIIIIIII.IIIIIII>BI$@0GIII
SRR036740.4 WICMT-SOLEXA2_FC20A5VAAXX:4:1:877:779 length=26 - 17 84738197 TATTACATTCCCTCTTACAGACAAAA HI29IDI<IIEIIIIIIIII&IIIII
SRR036740.3 WICMT-SOLEXA2_FC20A5VAAXX:4:1:884:705 length=26 - 5 129917611 TATATAATTCCAAATTTAGGCCTAAA IIIIIIIIIIIIIIIIIIIIIIIIII
SRR036740.9 WICMT-SOLEXA2_FC20A5VAAXX:4:1:876:896 length=26 + 7 14454197 TGAGTTTGTTTATATCGTGAATTATG IIII%IIIIII)I'I%@?=;I4I@I7

After:
SRR036740.6 WICMT-SOLEXA2_FC20A5VAAXX:4:1:880:684 length=26 + chr2 115333875 TTACAATAAGGAGAAAGGTGCATCTG IIIIIIIIIIIIIIIIIIIIIIIIII
SRR036740.1 WICMT-SOLEXA2_FC20A5VAAXX:4:1:875:740 length=26 + chr2 166030789 TATCGAGTCTCTTTTCAAAGCATTCA IIIIIIII.IIIIIII>BI$@0GIII
SRR036740.4 WICMT-SOLEXA2_FC20A5VAAXX:4:1:877:779 length=26 - chr17 84738197 TATTACATTCCCTCTTACAGACAAAA HI29IDI<IIEIIIIIIIII&IIIII
SRR036740.3 WICMT-SOLEXA2_FC20A5VAAXX:4:1:884:705 length=26 - chr5 129917611 TATATAATTCCAAATTTAGGCCTAAA IIIIIIIIIIIIIIIIIIIIIIIIII
SRR036740.9 WICMT-SOLEXA2_FC20A5VAAXX:4:1:876:896 length=26 + chr7 14454197 TGAGTTTGTTTATATCGTGAATTATG IIII%IIIIII)I'I%@?=;I4I@I7

The chr* column is actually a tab delimited column on its own with 1 or 2 digits (column #3) but somehow it does not show up here in the text. I want to add the characters 'chr' in front of each digit pair in that column.

Hope this clears up any confusion.

Thanks!

Your sample input file has blank-delimited fields so I worked with that, rather than tabs.

Try this ...
Daniel B. Martin

This proposed solution relies on columnar consistency rather than field separator characters.

Try this ...
Daniel B. Martin

To show layout accurately, use the CODE tags as described here https://www.linuxquestions.org/quest...do=bbcode#code

It should be like:

I am curious why the awk had to be so complicated?

Are you sure, it's working? I think it should be like:

Did you try it? Worked just fine for me. Also, how does your 'if' make sense? You are assigning a value, not testing it.

Only one reason: lack of experience. I am still on the awk learning curve. Your solution is simple and effective. Thank you for showing the way.

One minor quibble... OP said "The chr* column is actually a tab delimited column on its own ..."
Not clear on this. Perhaps he wants chr to stand apart.
If so, that is accomplished with a trivial change to your awk.Daniel B. Martin

Thank you for the replies guys. I will try the solutions later this afternoon and report back.

Halleluiah! Solved! All your answers helped solve it. Grail's solution was the shortest and simplest ;)

Thanks!

It actually didn't work on my system (returned no output), but addition of if statement did the job. Anyway, thanks to you.

When you say your system, is that solaris? I understand it has a different variant of awk, whereas most linux distros are using gawk or similar.