Re: How many chars read -r line can read from tty?

[Chet Ramey]

On 5/15/24 4:47 PM, Peng Yu wrote:
> Hi,
>
> read -r line; echo ${#line}
>
> The above code does not work when the input is long. I tried to paste
> to the terminal a string of 1024 characters. When I type return, I
> just hear beeping. read won't finish so that the length of $line can
> be printed.

man termios says:

"Each terminal device file has associated with it an input queue, into
which incoming data is stored by the system before being read by a
process.  The system imposes a limit, {MAX_INPUT}, on the number of bytes
that may be stored in the input queue."

$ grep INPUT 
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/sys/syslimits.h
#define MAX_INPUT                1024   /* max bytes in terminal input */


--
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/

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