W dniu 29.03.2024 o 19:08, Elliott Mitchell pisze: > On Fri, Mar 29, 2024 at 04:32:18PM +0100, Paul D wrote: >> Recommend avoiding -a and -o params. >> >> Use instead e.g. >> >> [ -n "$GUID" ] || [ "$KERNELPARTTYPE" = "6" ] || [ "$KERNELPARTTYPE" = "c" ] >> >> https://www.shellcheck.net/wiki/SC2166 > > The examples pointed to amounted to "be careful with untrusted input to > shell scripts". Build systems must already be pretty much 100% trusted. > If someone slips something problematic into one there is pretty much > nothing to be done about it. > > > I've been getting the feeling the whole community is slowly trying to > recreate SunOS 5.7^WSolaris 2.7^WSoliaris 7 (used to be a Sun Thiing, > but now everyone's version numbers tend to be inflated). Where > /bin/false, /bin/true and /bin/test were all Korne Shell scripts. > > This nominally saved development work since Korne shell has > implementations of all these internally. Problem is this killed > performance for any shell script /not/ written in a shell with those as > built-in. While Korne shell is very fast once it has finished parsing > its input, it is slow at parsing its scripts. > > Having `gunzip` be a shell script seems headed in this direction. The > above seems a similar sort of situation, adding an extra fork()/execve() > to avoid warnings. > > I'm placing SC2166 on my disregard list. Yes, this is nominally not well > defined, but unlike most warnings this one has a major impact on > performance. > > (fork()/execve() are the two most expensive routinely used system calls) >
Thanks, I did consider the execution penalty but as this script is small I decided to go with Paul's suggestion, and as bonus, just to avoid future noise around this, when someone else validates this script with shellcheck. -- TMN _______________________________________________ openwrt-devel mailing list openwrt-devel@lists.openwrt.org https://lists.openwrt.org/mailman/listinfo/openwrt-devel
