[nycbug-talk] nifty(1)

[Matthew Story]

On Wed, Feb 29, 2012 at 10:24 AM, Henry M <henry95 at gmail.com> wrote:

> A cool one I came across by accident. A fun way to create a plain text
> file. Redirect stdout of cat to a file, type your text, then close it with
> ctrl-d
>

sh(1) binds stdin to tty if there is nothing on stdin, e.g.:

$ xargs echo
hi
you
guys
^Dhi you guys
$ grep foo
bar
baz
foo
foo
^D

This is also how ed(1) works ... ! Very nifty indeed.


> Sample:
>
>> $ cat >filename
>> Hello, Talk
>> ^D
>> $ cat filename
>> Hello, Talk
>>
>
> Regards,
> -Henry
>
> On Thu, Dec 15, 2011 at 9:24 PM, William Baxter <
> web-nycbug at superscript.com> wrote:
>
>> Excerpts from Matthew Story's message of Thu Dec 15 00:54:24 -0500 2011:
>> > i believe the most portable version is slightly uglier:
>> >
>> > On Dec 14, 2011, at 6:13 PM, Isaac Levy wrote:
>> >
>> > >  shout() { echo "$0: $*" >&2; }
>> > >  barf() { shout "$*"; exit 111; }
>> > safe() { ${1+"$@"} || barf "cannot $*"; }
>> >           ^^^^^^^^ this bit is more reliable for sh on Solaris (real
>> Bourne shell)
>> >
>>
>> Delightful as the topic of Solaris compatibility may be I don't think
>> it's worth
>> going that far.  The ${1+"$@"} construct is indispensable for
>> compatibility in
>> cases when an empty list is legitimate while an unintended empty argument
>> is
>> not:
>>
>>  for ${1+"$@"}
>>
>> versus
>>
>>  for "$@"
>>
>> But an empty string and an empty list are both erroneous for safe().
>>  While the
>> execution details may vary from shell to shell, I consider it a case of
>> pilot
>> error to pass in either an empty argument or no argument to a function
>> that
>> requires a program.  A function cannot ultimately protect the caller from
>> his
>> own error.
>>
>> Cheers, W.
>> _______________________________________________
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>> talk at lists.nycbug.org
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>>
>
>
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-- 
regards,
matt
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