Re: grep question
The [c], I believe, is a character class containing only the letter c. If
you wanted to match "cron" or "tron" you could use '[ct]ron'.
In this case, the only effect is that the ps output for the grep process
won't match its own pattern, so you don't get the spurious item.
ap
----------------------------------------------------------------------
Andrew J Perrin - andrew_perrin@unc.edu - http://www.unc.edu/~aperrin
Assistant Professor of Sociology, U of North Carolina, Chapel Hill
269 Hamilton Hall, CB#3210, Chapel Hill, NC 27599-3210 USA
On Mon, 8 Apr 2002, Johann Spies wrote:
> In the grep's info page I find the following which works as said. But
> I want to know why. What does the [c] do in this case?
>
> ------------------------
> 7. Why do people use strange regular expressions on `ps' output?
>
> ps -ef | grep '[c]ron'
>
> If the pattern had been written without the square brackets, it
> would have matched not only the `ps' output line for `cron', but
> also the `ps' output line for `grep'.
>
> -------------------------------
>
> Johann
> --
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> Informasietegnologie, Universiteit van Stellenbosch
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>
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