awk to add symbol to specific field

Shell Programming and Scripting
1

Trying to use awk to add a . to $4 . The input and output is tab-delimeted , but the awk seems to add a . in front of $5 and is space-delimeted . It seems close, but I am not able to produce the desired output . Thank you :).

file

chr1    948895    949015    chr1:948895-949015     ISG15
chr1    949311    949431    chr1:949311-949431     ISG15
chr1    949431    949551    chr1:949431-949551     ISG15

awk with current output

awk -F'\t' -v OFS='\t' '{$5="."$5;print $0}' file
chr1    948895    949015    chr1:948895-949015    . ISG15
chr1    949311    949431    chr1:949311-949431    . ISG15
chr1    949431    949551    chr1:949431-949551    . ISG15

desired output

chr1    948895    949015    chr1:948895-949015     .     ISG15
chr1    949311    949431    chr1:949311-949431     .     ISG15
chr1    949431    949551    chr1:949431-949551     .     ISG15

Maybe not the best, but seems to work:

awk -F'\t' -v OFS='\t' '{print $1, $2, $3 ,".", $4, $5}' file
2

Hello cmccabe,

I am pretty sure it's happening because of your Input_file is not having all the fields as TAB delimited, when you make all fields tab delimited it will not misplace it.

Thanks,
R. Singh