On Mon, Jun 23, 2008 at 10:07:27AM +0200, Michael Meskes wrote:
With our move to dash as sh we have to remove all bashisms from scripts run by /bin/sh. However, checkbashism seems to moan about clauses that work in dash as well. I don't know in which shells a trap with a signal numberis guaranteed to work, but it seems to work well in dash.
As far as I'm aware, there are three shells in Debian that can be used as /bin/sh: bash, dash, and posh[0]. bash is, in general, the most featureful of these. Just because something works in one does not mean that it works in all of them. Notably, posh implements the most minimal set of features, and last time I checked, my system failed to boot because scripts were using features not mandated by policy. So, if you're going to fix bugs due to bashisms, please fix them all. They are all policy violations, and there's no reason to fix only some bugs. As for the signal numbers, different architectures have different signal numbers. See signal(7), but the most common ones *are* identical. However, signals such as SIGUSR1 and SIGUSR2 are not, and using a number for these will break on at least alpha, mips, mipsel, and sparc[1]. Using names is not only more portable, it is more explicit. Everyone knows what SIGABRT does, but not everyone knows what signal 4 does. Think of using signal numbers as using magic numbers: it's a bad programming practice. Also, as GNU/kFreeBSD becomes more usable, it will be important to have shell scripts work across kernels. The FreeBSD kernel does not match any Linux architecture in its assignment of signal numbers, so fixing these now is a good idea. [0] It would be nice if zsh were added to this list, but I'm not holding my breath. [1] Assuming, of course, that most people use i386 or amd64 as their main platform, and program accordingly. Judging by the number of FTBFS bugs on sparc due to alignment problems, this is a safe assumption. -- brian m. carlson / brian with sandals: Houston, Texas, US +1 713 440 7475 | http://crustytoothpaste.ath.cx/~bmc | My opinion only troff on top of XML: http://crustytoothpaste.ath.cx/~bmc/code/thwack OpenPGP: RSA v4 4096b 88AC E9B2 9196 305B A994 7552 F1BA 225C 0223 B187
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