On Thu, Mar 02, 2006 at 09:19:02AM -0800, David Kirchner wrote: > On 3/2/06, Kevin B. McCarty <[EMAIL PROTECTED]> wrote: > > Hi list, > > > > Could someone tell me why the following works in zsh but not in > > bash/posh/dash? > > > > benjo[3]:~% echo foo bar baz | read a b c > > benjo[4]:~% echo $a $b $c > > foo bar baz > > > > If I try the same with bash (or other sh-compatible shells), the > > variables $a $b and $c are unset. From the bash man page: > > ... > > So "read" claims to read from the standard input, but it doesn't > > actually seem to happen when a pipe is involved. > > What's happening here is that the pipe is causing a subshell to be > spawned, which is then parsing the command "read a b c".
> > http://linuxgazette.net/issue57/tag/1.html > > The example he gives, with the < <() syntax, worked in bash, but not > in Debian or FreeBSD's /bin/sh. In more recent bashes, the following should work as well #!/bin/bash read a b c <<<`echo foo bar baz` echo $a $b $c The <<< ("here strings") are an extension of the "here document" syntax, IOW, the string given after <<< is supplied as stdin to the command. Then, there's another variant, which is about as ugly as it can get... It should, however, work with most bourne shell compatible shells: #!/bin/sh eval `echo foo bar baz | (read a b c; echo "a='$a';b='$b';c='$c'" )` echo $a $b $c To get the variable's values from the subshell back to the main shell, a shell code fragment is written on stdout, captured with backticks, and then eval'ed in the main shell... (this is the moment when I usually switch to some other scripting language -- if not before :) Cheers, Almut -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
