Pabbisetty.henr@xerox.com (Nagesh Pabbisetty) (02/22/89)
> I am trying to use this invokation: > > if (isatty (stdin)) Use the following segment of code: if (isatty(fileno(stdin))) { printf("Hello> "); fflush(stdout); } Reason why (isatty (stdin)) will not work: isatty requires a file descriptor as an argument but you were trying to use it with a file pointer. Hope this helps... Nagesh 716-427-1827 / 5458
dave@tikal.Teltone.COM (news) (02/24/89)
In article <18432@adm.BRL.MIL> Pabbisetty.henr@xerox.com (Nagesh Pabbisetty) writes: >> I am trying to use this invokation: >> >> if (isatty (stdin)) > > >Use the following segment of code: > > if (isatty(fileno(stdin))) { > printf("Hello> "); > fflush(stdout); > } Now my question is, how would you do this in a script? Either C or Bourne. In C shell, I have this code, but it doesn't appear to work. if ({`test -t 0`}) then echo -n "==> " else echo -n "--> " endif It should print "-->" if stdin isn't coming from a terminal, but it doesn't seem to work that way. It always prints "==>". -- ---------------------------------------- David Karr dave@tikal.Teltone.COM or ...uw-beaver!tikal!dave Teltone Corp., 10801 120th Ave. NE, Kirkland, WA 98033 (206)827-9626 "The above statements do not necessarily reflect the opinions of my employer."
lvc@cbnews.ATT.COM (Lawrence V. Cipriani) (02/24/89)
In article <1161@tikal.Teltone.COM>, dave@tikal.Teltone.COM (news) writes:
+ Now my question is, how would you do this in a script? Either C or Bourne.
+ In C shell, I have this code, but it doesn't appear to work.
+
+ if ({`test -t 0`}) then
+ echo -n "==> "
+ else
+ echo -n "--> "
+ endif
What you want is (Bourne shell or Korn shell):
if [ -t 0 ]
then
echo stdin is a terminal
else
echo stdin is not a terminal
fi
--
Larry Cipriani, att!cbnews!lvc or lvc@cbnews.att.commaart@cs.vu.nl (Maarten Litmaath) (02/24/89)
In article <1161@tikal.Teltone.COM> dave@tikal.UUCP (David Karr) writes:
\if ({`test -t 0`}) then
if ({ test -t 0 }) then
or
if { test -t 0 } then
You want the exit status instead of the standard output from test.
--
"Those who do not understand Henry |Maarten Litmaath @ VU Amsterdam:
Spencer are condemned to reinvent DOS." |maart@cs.vu.nl, mcvax!botter!maartalfie@warwick.UUCP (Nick Holloway) (02/28/89)
In article <1161@tikal.Teltone.COM> dave@tikal.UUCP (David Karr) writes: > In article <18432@adm.BRL.MIL> Pabbisetty.henr@xerox.com (Nagesh Pabbisetty) writes: > >> [Doing isatty(FILE*) instead of isatty(int)] > > > > [Correct solution of isatty(fileno(FILE*))] > > Now my question is, how would you do this in a script? Either C or Bourne. The method I use is tty(1). This will print out the name of the terminal attached to stdin. This can be used more generally by using the -s flag (No report just, return the status) and redirecting the input. This script is an example of this (call it demo): #!/bin/sh if tty -s <&0 # redirect from stdin then echo "stdin: from terminal" else echo "stdin: not from terminal" fi if tty -s <&1 # redirect from stdout then echo "stdout: from terminal" else echo "stdout: not from terminal" fi if tty -s <&2 # redirect from stderr then echo "stderr: from terminal" else echo "stderr: not from terminal" fi Try running as: $ demo $ demo | cat $ demo 2>/dev/null $ demo 2>&1 | cat $ demo </dev/null 2>&1 | cat > In C shell, I have this code, but it doesn't appear to work. > [C-Shell script to try and find out whether connected to terminal] I'm afraid I don't speak c-shell, so I can't comment on your script - although if you are only interested in whether stdin is connected to terminal you can use "tty -s" as above. When it comes to checking other streams - I don't know enough about C-shell redirection (other than it is not as flexible as sh). -- JANET : alfie@uk.ac.warwick.cs | `O O' | Nick Holloway BITNET/EARN : alfie%uk.ac.warwick.cs@ukacrl | // ^ \\ | Comp Sci Dept INTERNET : alfie%cs.warwick.ac.uk@nss.cs.ucl.ac.uk +---------+ Uni of Warwick UUCP : ..!mcvax!ukc!warwick!alfie, alfie@warwick.UUCP | Coventry, UK.