Re: Several reasons why debian should not use bash for /bin/sh

[Martin Schulze <joey@kuolema.Infodrom.North.DE>]

Chris Ulrich wrote:
>   I'm new to debian but I'm not new to either unix or linux.  I recently
> installed debian on my laptop.  On my prior linux setup, I had pdksh as
> /bin/sh.  While I sometimes had problems with scripts, I never ran into
> showstoppers.  When I made ash or pdksh /bin/sh on my debian setup, things
> stopped working.  I consider this to be a serious problem with debian.

If there are still scripts that have "#! /bin/sh" at the top but use
non-plain-bourne shell commands, i.e. bashisms, this is a bug in that
very package.  To fix this somebody has to file appropriate bugreports
and let the maintainer do their job.


> Speed: bash is much slower than ash or pdksh.  From init scripts to 
>        cron or day to day shell scripts, /bin/sh gets run many thousands
>        of times.  Because bash is slower, this results in a slower
>        feeling machine.  For example my computer boots noticeably faster
>        when I use pdksh or ash instead of bash.

Maybe this is time for me to add a comment.  Bash scripts can be used
to increas the speed of scripts extremly.  When your script calls awk,
cut, grep, perl etc. it *is* slow.  Much of the functionality is also
available in plain bash.

> Safety: Bash, at least in the debian distribution I've installed, is linked
>        against 5 libraries (readline, curses, dl, c and ld-linux).  If
>        any one of these libraries gets hosed, /bin/sh stops working and
>        this effectively kills the system.  A smaller, simpler shell would
>        be less vulnerable to library problems.

This has shown to be a problem when the first people killed^H^H^H^H^H^Hconverted
their system from libc5 to libc6.

> Compatibility: People are tempted to (and in fact do) write scripts that
>        use bash specific extensions when explicitly calling /bin/sh.  

These are bugs that have to be reported.

Regards,

	Joey

-- 
There are lies, statistics and benchmarks.


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