Re: [R] shQuote and cat

From: Duncan Murdoch <>
Date: Wed, 23 Jul 2008 14:10:37 -0400

On 7/23/2008 12:20 PM, Vadim Organovich wrote:
> Dear R-users,
> It is my understanding that cat(shQuote(a.string)) should print the origintal a.string. Is this right?

No, cat(a.string) should print the original a.string. shQuote(a.string) adds quotes so that a.string can be used in the shell.

> I am not sure cat() correctly prints strings which are generated by triple-shQuote():

>> shQuote(shQuote("a"))

> [1] "\"\\\"a\\\"\""

>> cat(shQuote(shQuote(shQuote("a"))), '\n')
> "\"\\"a\\"\<file://\\"a\\"\>""

That's a very strange result. I tried the obsolete version of R that you're using, and I didn't see it. I get this:

 > cat(shQuote(shQuote(shQuote("a"))), '\n') "\"\\"a\\"\""

Duncan Murdoch

> As you can see the latter string has fewer quoting '\' than the former.
> cat() of double shQuote works as expected:

>> shQuote("a")

> [1] "\"a\""
>> cat(shQuote(shQuote("a")), '\n')

> "\"a\""
>> version

> _
> platform i386-pc-mingw32
> arch i386
> os mingw32
> system i386, mingw32
> status
> major 2
> minor 6.1
> year 2007
> month 11
> day 26
> svn rev 43537
> language R
> version.string R version 2.6.1 (2007-11-26)
> Am I missing something?
> Thanks,
> Vadim
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> and provide commented, minimal, self-contained, reproducible code. mailing list PLEASE do read the posting guide and provide commented, minimal, self-contained, reproducible code. Received on Wed 23 Jul 2008 - 18:18:12 GMT

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