output to a file:

git log > filename.log


 git log --pretty=format:"%s" --since=15.weeks  >  aaaa.log 

 

To specify a format, like you want everything on one line

git log --pretty=oneline >filename.log

or you want it a format to be emailed via a program like sendmail

git log --pretty=email |email-sending-script.sh

to generate JSON, YAML or XML it looks like you need to do something like:

git log --pretty=format:"%h%x09%an%x09%ad%x09%s"

This gist (not mine) perfectly formats output in JSON:https://gist.github.com/1306223

See also:

• http://git-scm.com/book/en/Git-Basics-Viewing-the-Commit-History
• Git how to save a preset git log --format
• How to parse the output of git log