#!/bin/bash considered harmful

When one writes a shell script there are a variety of shebang lines that could be used:

• #!/bin/sh
• #!/usr/bin/env bash
• #!/bin/bash

or one of many other options.

Of these only the first two are possibly correct.

Using #!/bin/bash is wrong because:

• Sometimes bash isn't installed.
• If it is installed, it may not be in /bin
• If it is in /bin, the user may have decided to set PATH to use a different installation of bash. Using an absolute path like this overrides the user's choices.
• bash shouldn't be used for scripts intended for portability

If you have bash specific code use #!/usr/bin/env bash. If you want more portable code try using Debian's checkbashism to find instances of non-POSIX compliant shell scripting.

Some git-svn notes

When working with a subversion repository I often miss the use git features. However, it is possible for git to speak the subversion protocol:

Cloning the initial repository

$git svn clone svn://svn.freebsd.org/base/head


Resuming an interrupted git svn clone

It is really annoying when you start a git svn clone process overnight and come back to find that it stopped in the middle. Luckily, there is a really simple way to recover - without spending hours to redownload what you already have.

$git svn fetch
$git svn rebase

Committing the final patch

There are a lot of workflows for this, but I prefer the cherry-pick approach:

$git checkout master
$git svn rebase
$git cherry-pick commit-id
$git svn dcommit