Git how to save a preset git log --format

Considering the git log manual page mentions:

--pretty[=<format>]
--format[=<format>]

Pretty-print the contents of the commit logs in a given format, where can be one of oneline, short, medium, full, fuller, email, raw and format:. When omitted, the format defaults to medium.

the <format> can only have predefined values.
That only leaves you the possibility to define an alias as a shortcut for that command.

[alias]
        jespers_favourite = log --pretty=format:"%h%x09%an%x09%ad%x09%s"

or

[alias]
        compactlog = log --pretty=format:"%h%x09%an%x09%ad%x09%s"

You can configure the default pretty format using git-config. From the git-config documentation:

 format.pretty
           The default pretty format for log/show/whatchanged command, See git-log(1), git-show(1), git-whatchanged(1).

For example:

git config --add format.pretty fuller

or original poster's desired format:

git config --add format.pretty "%h%x09%an%x09%ad%x09%s"

Like with other git config settings, format.pretty may be set at the global, system, or repository scope (default).

In newer versions of Git (confirmed with v1.7.8) it is possible to set named pretty-print log formats using git config pretty.named_format. These can be set at a machine-wide, user or file level with the <file-option> argument.

To create a log format called jespers_favourite or the whole machine use --system

git config --system pretty.jespers_favourite "%h%x09%an%x09%ad%x09%s"

For single user use '--global'

git config --global pretty.jespers_favourite "%h%x09%an%x09%ad%x09%s"

Leaving the <file-option> argument blank will default to setting the config file of the current repository, .git/config unless defined otherwise.