How to accept input from stdin?

07-03-08, 07:24 PM

PengYu.UT

Hi,

I try to make a wrapper around an existing program, which would behave
exactly the same as the original one. But my following attempt was
failed. Would you pleaes let me know what is the correct way?

Thanks,
Peng

$cat ./my_tee.sh
#!/bin/bash

read

echo $REPLY | tee $*
$ cat abc
a
b
c
$ cat abc | ./my_tee.sh efg
a

07-03-08, 07:31 PM

On Thursday 3 July 2008 20:24, PengYu.UT wrote:

[..]
>
> read
>
> echo $REPLY | tee $*
> $ cat abc
> a
> b
> c
> $ cat abc | ./my_tee.sh efg
> a

What about

cat abc | efg

or, better

efg < abc

or, better yet, explain what you're trying to do?

07-03-08, 08:06 PM

PengYu.UT

On Jul 3, 1:31 pm, pk <p...@pk.invalid> wrote:
> On Thursday 3 July 2008 20:24, PengYu...@gmail.com wrote:
>>
>>
>>
> What about
>
> cat abc | efg
>
> or, better
>
> efg < abc
>
> or, better yet, explain what you're trying to do?

I'm trying to mimic an existing command. Of course, in practice, the
new command is different from the old one, otherwise, this is no
point. As a simplification, in my example, the new command (my_tee.sh)
shall do the same thing as the old command (tee).

The point is that I want the new one accept exactly the same set of
command line arguments as well as the stdin as the old one.

Thanks,
Peng

07-03-08, 08:15 PM

OldSchool

On Jul 3, 2:24 pm, "PengYu...@gmail.com" <PengYu> wrote:
[..]
>
> read
>
> echo $REPLY | tee $*
> $ cat abc
> a
> b
> c
> $ cat abc | ./my_tee.sh efg
> a

most shells support "here-docs" so something like:

./my_tee.sh efg <<-ENDIT
a
b
c
ENDIT

ought to work, or look at "expect".

07-03-08, 08:41 PM

Chris F.A. Johnson

On 2008-07-03, PengYu.UT wrote:
> Hi,
>
> I try to make a wrapper around an existing program, which would behave
> exactly the same as the original one. But my following attempt was
> failed. Would you pleaes let me know what is the correct way?

That depends on what you want to do.

> $cat ./my_tee.sh
> #!/bin/bash
>
> read
>
> echo $REPLY | tee $*
> $ cat abc
> a
> b
> c
> $ cat abc | ./my_tee.sh efg
> a

How about:

tee "$@" | do_whatever

Replace 'do_whatever' with whatever you want to do to the input.

07-03-08, 09:35 PM

Bill Marcum

On 2008-07-03, PengYu.UT <PengYu.UT> wrote:
[..]
>
> read
>
> echo $REPLY | tee $*
> $ cat abc
> a
> b
> c
> $ cat abc | ./my_tee.sh efg
> a

IFS=
while read; do
echo "$REPLY"
done |tee "$@"

or

IFS=
while read; do
echo "$REPLY" | tee -a "$@"
done

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