[arch-general] [PATCH 04/48] Use [[ ]] instead of [ ] for conditional checking when running in bash.
It is worth 10 - 30% speedup whenever you want to compare something. --- functions |2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/functions b/functions index 6df8c5e..9b348b7 100644 --- a/functions +++ b/functions @@ -40,7 +40,7 @@ unset TERM_COLORS unset TZ # colors: -if [ $USECOLOR = YES -o $USECOLOR = yes ]; then +if [[ $USECOLOR = YES || $USECOLOR = yes ]]; then C_MAIN=\033[1;37;40m # main text C_OTHER=\033[1;34;40m # prefix brackets -- 1.7.1
Re: [arch-general] [PATCH 04/48] Use [[ ]] instead of [ ] for conditional checking when running in bash.
Am 30.06.2010 23:47, schrieb Victor Lowther: It is worth 10 - 30% speedup whenever you want to compare something. Where do you get this from? I always used [ ], and I found it sufficient. Why is [[ ]] faster? -if [ $USECOLOR = YES -o $USECOLOR = yes ]; then +if [[ $USECOLOR = YES || $USECOLOR = yes ]]; then Why do you get rid of the quoting here? Quoting is nice. signature.asc Description: OpenPGP digital signature
Re: [arch-general] [PATCH 04/48] Use [[ ]] instead of [ ] for conditional checking when running in bash.
On Wed, Jun 30, 2010 at 17:56, Thomas Bächler tho...@archlinux.org wrote: Am 30.06.2010 23:47, schrieb Victor Lowther: It is worth 10 - 30% speedup whenever you want to compare something. Where do you get this from? I always used [ ], and I found it sufficient. Why is [[ ]] faster? -if [ $USECOLOR = YES -o $USECOLOR = yes ]; then +if [[ $USECOLOR = YES || $USECOLOR = yes ]]; then Why do you get rid of the quoting here? Quoting is nice. Quoting is not needed in [[ and it makes the code uglier.
Re: [arch-general] [PATCH 04/48] Use [[ ]] instead of [ ] for conditional checking when running in bash.
On Wed, 2010-06-30 at 23:56 +0200, Thomas Bächler wrote: Am 30.06.2010 23:47, schrieb Victor Lowther: It is worth 10 - 30% speedup whenever you want to compare something. Where do you get this from? I always used [ ], and I found it sufficient. Why is [[ ]] faster? [[ ]] is faster because it is bash syntax, not a builtin command like [ is. In most programs, both are fast enough, but you an see the difference if you run otherwise identical tests in a loop one million times. -if [ $USECOLOR = YES -o $USECOLOR = yes ]; then +if [[ $USECOLOR = YES || $USECOLOR = yes ]]; then Why do you get rid of the quoting here? Quoting is nice. Because [[ ]] is bash syntax instead if a builtin comand, it relaxes the usual expansion rules -- inside of [[ ]], word splitting and pathname expansion are not performed, so you only have to quote strings if they need to be single-quoted. http://wiki.bash-hackers.org/syntax/ccmd/conditional_expression has more info. -- Victor Lowther LPIC2 UCP RHCE
Re: [arch-general] [PATCH 04/48] Use [[ ]] instead of [ ] for conditional checking when running in bash.
2010/7/1 Daenyth Blank daenyth+a...@gmail.com: On Wed, Jun 30, 2010 at 17:56, Thomas Bächler tho...@archlinux.org wrote: Am 30.06.2010 23:47, schrieb Victor Lowther: It is worth 10 - 30% speedup whenever you want to compare something. Where do you get this from? I always used [ ], and I found it sufficient. Why is [[ ]] faster? -if [ $USECOLOR = YES -o $USECOLOR = yes ]; then +if [[ $USECOLOR = YES || $USECOLOR = yes ]]; then Why do you get rid of the quoting here? Quoting is nice. Quoting is not needed in [[ and it makes the code uglier. Ditto. May I also suggest a link[1] to those that do not know all the beauties of double square brackets? By the way, the whole BashFAQ in there is really interesting, it has lots of advanced tips 'n tricks. Corrado [1] http://mywiki.wooledge.org/BashFAQ/031
Re: [arch-general] [PATCH 04/48] Use [[ ]] instead of [ ] for conditional checking when running in bash.
Am 01.07.2010 00:22, schrieb Victor Lowther: On Wed, 2010-06-30 at 23:56 +0200, Thomas Bächler wrote: Am 30.06.2010 23:47, schrieb Victor Lowther: It is worth 10 - 30% speedup whenever you want to compare something. Where do you get this from? I always used [ ], and I found it sufficient. Why is [[ ]] faster? [[ ]] is faster because it is bash syntax, not a builtin command like [ is. In most programs, both are fast enough, but you an see the difference if you run otherwise identical tests in a loop one million times. -if [ $USECOLOR = YES -o $USECOLOR = yes ]; then +if [[ $USECOLOR = YES || $USECOLOR = yes ]]; then Why do you get rid of the quoting here? Quoting is nice. Because [[ ]] is bash syntax instead if a builtin comand, it relaxes the usual expansion rules -- inside of [[ ]], word splitting and pathname expansion are not performed, so you only have to quote strings if they need to be single-quoted. http://wiki.bash-hackers.org/syntax/ccmd/conditional_expression has more info. Sounds nice. This will probably mean that I will apply all the patches that do this transition - however, it might probably be nicer to squash all of those into one commit. signature.asc Description: OpenPGP digital signature
Re: [arch-general] [PATCH 04/48] Use [[ ]] instead of [ ] for conditional checking when running in bash.
On Thu, 2010-07-01 at 00:24 +0200, bardo wrote: 2010/7/1 Daenyth Blank daenyth+a...@gmail.com: On Wed, Jun 30, 2010 at 17:56, Thomas Bächler tho...@archlinux.org wrote: Am 30.06.2010 23:47, schrieb Victor Lowther: It is worth 10 - 30% speedup whenever you want to compare something. Where do you get this from? I always used [ ], and I found it sufficient. Why is [[ ]] faster? -if [ $USECOLOR = YES -o $USECOLOR = yes ]; then +if [[ $USECOLOR = YES || $USECOLOR = yes ]]; then Why do you get rid of the quoting here? Quoting is nice. Quoting is not needed in [[ and it makes the code uglier. Ditto. May I also suggest a link[1] to those that do not know all the beauties of double square brackets? By the way, the whole BashFAQ in there is really interesting, it has lots of advanced tips 'n tricks. Corrado [1] http://mywiki.wooledge.org/BashFAQ/031 greycat and friends are awesome, it is true. I learned alot reading gregs wiki and hanging out on #bash. -- Victor Lowther LPIC2 UCP RHCE
