rbarrell@lgnp1.LS.COM (Robert Barrell) (06/22/89)
[The machine through which I usually access the newsgroups had a bit of
a burp, so please forgive me if I'm repeating an answer, here.]
I don't know if it was ever answered, or not, but someone had asked about
how to determine if the program they were running was being used directly, or
in a pipe. In glancing through the manuals, I happened to notice the isatty()
C call, and what it does, which prompted me to examine the "tty" shell command.
In doing so, I found that "tty" returns a 0 if standard-input is a terminal,
and returns a 1 if it isn't. Also, with the "-s" option, "tty" can be made
silent, so the exit code may be used without having to redirect the output of
"tty" to /dev/null. Thus, the following script will tell you if it is being
run in a pipe or not:
if [ `tty -s;echo $?` = 0 ]
then
echo "terminal"
else
echo "pipe"
fi
I hope this isn't to late (or already redundant) to be of use to the
person who originally asked the question.
------------------------------------------------------------------------------
Robert Barrell
"Hodgepodge" - Sysop of Milo's Meadow - A Citadel/UX BBS
215-323-0497 - 300/1200/2400 - 24hrs. - login as "bbs"
------------------------------------------------------------------------------maart@cs.vu.nl (Maarten Litmaath) (07/04/89)
rbarrell@lgnp1.LS.COM (Robert Barrell) writes:
\
\ if [ `tty -s;echo $?` = 0 ]
\ then
\ echo "terminal"
\ else
\ echo "pipe"
\ fi
What an `interesting' way to accomplish the following:
if tty -s
then
echo terminal
else
echo pipe
fi
or even
tty -s && echo terminal || echo pipe
--
"I HATE arbitrary limits, especially when |Maarten Litmaath @ VU Amsterdam:
they're small." (Stephen Savitzky) |maart@cs.vu.nl, mcvax!botter!maart