General :: Sed Adds A Space Instead Of Tab At End Of Line

The objective is to read a file line by line, add a tab at end of each line and add a value(number) after the tab.

My script:

Code:

Report.tsv before running the script for the first time:

Code:

At the end of first run, each line of Report.tsv gets appended by a space instead of a tab. On the other hand each line of Report.tsv gets appended by tab at the end of second run onwards.

This was realized when Report.tsv was imported in open office spreadsheet. First set of appended values get merged into the original column (Strings) and the subsequent appended values fall in distinct columns.