add strand info to a bed file

Question

[bioguy24]

Is there a script/tool that can add strand (+/-) information to the fourth column of a bed file? I have a bed file (first few lines below) of 45,000 targets each chromosome, start, and stop. Thank you :).

Target Bed

chr1    955542    955763
chr1    957570    957852
chr1    976034    976270

Answer 1

[Pierre Lindenbaum]

sed 's/$/\t+/' < input.bed > output.bed

[bioguy24]

Works great... thank you :)

As I am learning these techniques do you mind briefly explaining how this works? Thank you very much.

[Pierre Lindenbaum]

• sed: program http://manpages.ubuntu.com/manpages/precise/en/man1/sed.1.html
• s substitute
• $ end of line
• \t+ tab followed by +