Date: Sun, 28 Sep 1997 11:23:03 +0930 From: Greg Lehey <grog@lemis.com> To: Joerg Wunsch <joerg_wunsch@uriah.heep.sax.de> Cc: hackers@FreeBSD.ORG, Mike Smith <mike@smith.net.au> Subject: Re: Timeout for sh(1) 'read' ?? Message-ID: <19970928112303.32188@lemis.com> In-Reply-To: <19970927163558.WP09379@uriah.heep.sax.de>; from J Wunsch on Sat, Sep 27, 1997 at 04:35:58PM %2B0200 References: <199709260748.RAA00456@word.smith.net.au> <19970927163558.WP09379@uriah.heep.sax.de>
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On Sat, Sep 27, 1997 at 04:35:58PM +0200, J Wunsch wrote: > As Mike Smith wrote: > >> Hiho folks, a question for the sh(1) studs amongst you : >> >> - I want to prompt for input using 'read', and have the read return in >> some fashion after a timeout. > > A quick search for the word `timeout' in the ksh93 man page unveils: > > TMOUT If set to a value greater than zero, TMOUT > will be the default timeout value for the > read built-in command. The select compound > command terminates after TMOUT seconds when > input is from a terminal. Otherwise, the > shell will terminate if a line is not > entered within the prescribed number of sec- > onds while reading from a terminal. (Note > that the shell can be compiled with a maxi- > mum bound for this value which cannot be > exceeded.) > > and: > > read [ -Aprs ] [ -d delim] [ -t timeout] [ -u > unit] [ vname?prompt ] [ vname ... ] > The shell input mechanism. One line is read and is > broken up into fields using the characters in IFS > as separators. [...] > > Posix doesn't seem to have any opinion for this, so it looks like just > creeping featurism on ksh's side. (Posix only mentions option -r.) pdksh and bash both use this variable just for command line prompts. Try this: bash$ TMOUT=5 bash$ (wait 5 seconds) Then bash dies on you. It doesn't work for what Mike's looking for. Greg
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