How to redirect Valgrind's output to a file?

valgrind --log-file="filename"

By default, Valgrind writes its output to stderr. So you need to do something like:

valgrind a.out > log.txt 2>&1

Alternatively, you can tell Valgrind to write somewhere else; see http://valgrind.org/docs/manual/manual-core.html#manual-core.comment (but I've never tried this).

You can also set the options --log-fd if you just want to read your logs with a less. For example :

valgrind --log-fd=1 ls | less