Working with Tab-Delimited files

Shell Programming and Scripting
1

I have a tab-Delimited file:
Eg:
'test' file contains:
a<tab>b<tab>c<tab>....

Based on certain condition, I wanna increase the number of lines of this file.How do I do that
Eg:
If some value in the database is 1 then one line in 'test' file is fine..
If some value in the database is 2 then 2 lines in the 'test' file is required with the second line not matching the first line(this is req since i wanna perform a replace command later(Eg: replace 'a' with '1')

Eg:
'test' file will then contain:
a<tab>b<tab>c<tab>....
d<tab>e<tab>f<tab>....

i need to simulate this using a shell scripts..kindly help me..

2

This is not at all clear.

Why don't you try explaining what you really want to do, instead of what you think you need to do. The 'i wanna replace' means this is not the whole problem just one step.