On Sat, 28 Jul 2007, Mike Branda wrote:
> Slug,
>
> I have a bash script I'm playing with that reads input from a pipe. I
> want to add some error handling to the effect of when the script is
> called by itself and no information is piped to it, it exits and/or
> exits and complains. The problem I have is that I'm doing a "while read
> line do" and if there's no data coming in, it sits there waiting on the
> read. I've tried to use a if [ -s /dev/stdin ] conditional before the
> while but to no success.
>
> Does anybody have an idea on this or on how to test stdin?
>
> examples:
>
> :~>cat lines.txt | myscript.sh -takeinput
> I've got input... echoing
> line 1
> line 2
> line 3
> :~>
> :~>myscript.sh -takeinput
> (sits here waiting for input or ctrl-c)
This might be of use to you:
BASH(1) BASH(1)
...
read [-ers] [-u fd] [-t timeout] [-a aname] [-p prompt] [-n nchars] [-d
delim] [name ...]
...
-t timeout
Cause read to time out and return failure if a complete
line of input is not read within timeout seconds. This
option has no effect if read is not reading input from
the terminal or a pipe.
It'll cause a delay, and is sort of a guessing game to pick the right
timeout to allow manual entry of data or programs that wait a while, but
that's better than waiting forever IMO.
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