pgindent vs dash

For those who don't know, pgindent is the tool used to indent the source code of PostgreSQL. dash is the shell that ships as /bin/sh on at least Ubuntu.

pgindent requires indent from BSD (we use a patched version from NetBSD, the source is available on the PostgreSQL ftp site), and specifically does not work with GNU indent. Guess what Ubuntu ships with.

The solution is of course a small script that runs BSD indent from a different directory, and also points out the typedefs.list file from the PostgreSQL git repo. Something like this:

#!/bin/sh

export PATH=src/tools/pgindent:$PATH
src/tools/pgindent/pgindent src/tools/pgindent/typedefs.list $*

Spot the error? Yeah, that calls /bin/sh, which is dash. Which gives some really interesting results with pgindent, none of which are what you expect.

So if you run pgindent through a script like this, be sure to use /bin/bash and not /bin/sh!


Comments

Interesting post, thank you. As for the sh problem, the following shebang line should work: #!/usr/bin/env bash

Posted on Jan 18, 2011 at 17:03 by Hannes Just.

Oh, just using #!/bin/bash works fine. It's /bin/sh that doesn't (and AFAIK it *does* work if /bin/sh is actually sh and not dash)

Posted on Jan 18, 2011 at 17:05 by Magnus.

Not every distribution will install bash in /bin. Some will install bash only in /usr/bin/bash, so hard-coding its path will fail on those systems. Debian and Ubuntu are using the light-weight dash to speed up their boot process. It's not fully compatible with bash. It's not a requirement for distributions that /bin/sh actually is bash. Basically, /bin/sh just has to be smart enough to run init.d scripts. Therefore, if you depend on certain bash functionality (those fancy expansion features come to my mind), request bash instead of sh through the shebang.

Posted on Jan 18, 2011 at 17:27 by Hannes Just.