Re: How to determine terminal size when piped data to STDIN?

[hanenkamp]

I don't know if this is a typical option, but my man-page for stty shows a --file option where you can pick the file to check the parameters on. So, on Linux I can do this:

echo foo | perl -e '$x=`stty -a --file=/dev/stdin`; print "\$x=$x\n";'

and get:

speed 38400 baud; rows 50; columns 131; line = 0;
intr = ^C; quit = ^\; erase = ^?; kill = ^U; eof = ^D; eol = <undef>;
eol2 = <undef>; start = ^Q; stop = ^S; susp = ^Z; rprnt = ^R; werase =
+ ^W;
lnext = ^V; flush = ^O; min = 1; time = 0;
-parenb -parodd cs8 -hupcl -cstopb cread -clocal -crtscts
-ignbrk -brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr icrnl ixo
+n -ixoff
-iuclc -ixany -imaxbel
opost -olcuc -ocrnl onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs
+0 vt0 ff0
isig icanon iexten echo echoe echok -echonl -noflsh -xcase -tostop -ec
+hoprt
echoctl echoke

Since my Unix experience is pretty well limited to Linux, I can't be much help on other platforms.

Update: I made a mistake, I used /dev/stdout in my actual test but wrote /dev/stdin here. If you have access to any console device and a --file option, it would work. However, as mushu points out below, that is not the case.

[mushu]

HP-UX doesn't appear to have the --file option for its stty command. BUT, it probably wouldn't matter, since it would be called as a child process, and children inherit their parent's environment, thus STDIO for the stty child process would be the same as the parent's STDIO and not readable either.