Comment by chasil

12 hours ago

Try using the Windows busybox port of "Bash":

It has a subset of bash implemented on Ash/Dash. Arrays are not supported, but it is quite fast.

The forking problem is still present, though.

3 comments

chasil

Cygwin bash isn't slow either. The problem is a typical bash script isn't a series of bash operations, it's a series of command line program executions.

For example, someone might do something like this (completely ignoring the need to quote in the interests of illustrating the actual issue, forking):

    for x in *; do
      new_name=$(echo $x | sed 's/old/new/')
      mv $x $new_name
    done

Instead of something like this:

    for x in *; do
      echo $x
    done | sed -r 's|(.*)old(.*)|mv \1old\2 \1new\2|' | grep '^mv ' | bash

This avoids a sed invocation per loop and eliminates self-renames, but it's harder to work with.

Of course the code as written is completely unusuable in the presence of spaces or other weird characters in filenames, do not use this.

emmelaich 1 hour ago

You could also use the inbuilt substitution mechanism:

    $ parameter='fisholdbits'
    $ echo ${parameter/old/new}
    fishnewbits

chasil 3 hours ago

No, seriously, give an ash-derivative a try.
Dash has been benchmarked as 4x faster than bash. The bash manpage ends by stating that "bash is too big, and too slow."