Configuration Information [Automatically generated, do not change]:
Machine: i486
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS: -DPROGRAM='bash' -DCONF_HOSTTYPE='i486'
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='i486-pc-linux-gnu'
-DCONF_VENDOR='pc' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash'
-DSHELL -DHAVE_CONFIG_H -I. -I../bash -I../bash/include -I../bash/lib
-g -O2 -Wall
uname output: Linux cargocult 2.6.22-14-generic #1 SMP Tue Feb 12
07:42:25 UTC 2008 i686 GNU/Linux
Machine Type: i486-pc-linux-gnu
Bash Version: 3.2
Patch Level: 25
Release Status: release
Description:
${var//pattern/} style replacement is very slow for even
moderately large strings.
String length vs. user time for a simple example with many
replacements:
length: 1000 user: 0m0.112s
length: 2000 user: 0m0.660s
length: 3000 user: 0m1.968s
length: 4000 user: 0m4.368s
length: 5000 user: 0m8.101s
This should take a linear (or near-linear) amount of time;
it looks like there is way too much reallocation and
copying happening.
Repeat-By:
[EMAIL PROTECTED]:/tmp$ string="$(seq -f %09g 500)."; echo
"length: ${#string}"; time string="${string//0/}"
length: 5000
real 0m8.119s
user 0m8.101s
sys 0m0.016s
