idea: statically-linked "busy-bash"

[Richard Neill]

Dear All,

Here's an idea that occurred to me. I'm not sure whether it's a great 
idea, or a really really stupid one, so please feel free to shoot it 
down. Anyway, there are an awful lot of shell scripts where a huge 
number of the coreutils get repeatedly called in separate processes. 
This call-overhead makes the scripts run noticeably slower.

What I'm suggesting is to experimentally build a version of bash which 
has   mv/cp/ls/stat/grep/....  all built in. This would be a rather 
bigger binary, (similar to busybox), but might allow much much faster 
execution of long scripts.

A very quick experiment shows that this might be worthwhile:

date;
for ((i=0;i<1000000;i++)); do echo -n ""; done;
date;
for ((i=0;i<10000;i++)); do /bin/echo -n ""; done;
date

Prints:
Thu Apr  9 07:05:19 BST 2009
Thu Apr  9 07:05:30 BST 2009
Thu Apr  9 07:05:47 BST 2009


In other words, 1E6 invocations of the builtin takes about 11
seconds, while 1E4 invocations of the standalone binary
takes 17 seconds. The builtin echo is therefore about
150 times faster.

What do you think?

Richard