On Mon, Nov 08, 2010 at 10:11:58PM -0800, John R Pierce wrote: > but, then, I'm not sure sh on solaris is quite exactly the same as sh on > aix. Right. There's no uber-standard /bin/sh. Very very old Unix systems had a /bin/sh that didn't even support functions. And let's not talk about the different "echo" commands between OSes. When writing portable code in /bin/sh you always have to make some assumptions. > anyways, aix users usually uses ksh. but ksh on linux is a > little sketchy. ksh93 is pretty good, but not quite as compatible as ksh88. ksh88 was the SVR4 standard shell (so solaris, aix, hpux, sco etc all had it). Unfortunately ksh88 wasn't free (speech) so pdksh was created and that's not quite compatible with ksh88 (eg 'echo hello | read a' gives different results). What I found funny was that zsh in ksh-compat mode was really really close (in 1993 I converted a 700 line ksh88 script to run under zsh in ksh-mode; required 2 changes in total). On CentOS5 ksh-20100202-1.el5_5.1 is ksh93. It's possible to write code that works identically in ksh93 and ksh88 and that's pretty portable. -- rgds Stephen