From: "Bart Schaefer" <schaefer@brasslantern.com>
To: Clint Adams <clint@zsh.org>, zsh-workers@sunsite.dk
Subject: Re: [goswin.brederlow@student.uni-tuebingen.de: Bug#131063: zsh: read -r removes \ in \\]
Date: Sun, 27 Jan 2002 21:32:09 +0000 [thread overview]
Message-ID: <1020127213209.ZM9378@candle.brasslantern.com> (raw)
In-Reply-To: <20020127202405.GB32151@dman.com>
On Jan 27, 3:24pm, Clint Adams wrote:
} Subject: [goswin.brederlow@student.uni-tuebingen.de: Bug#131063: zsh: read
}
} ----- Forwarded message from Goswin Brederlow <goswin.brederlow@student.uni-tuebingen.de> -----
}
} ~% echo "\\"
} \
} ~% echo "\\" | read -r i; echo "$i"
} \
} ~% echo "\\\\\\\\"
} \\
} ~% echo "\\\\\\\\" | read -r i; echo "$i"
} \
}
} The manpage says read -r does not remove \.
`read -r' didn't remove the backslash. `echo "$i"' removed it, as was
pointed out a moment later:
} Also echo removes \:
}
} ~% echo "\\\\"
} \
}
} bash will print \\ as intendet. Any reason? (ksh/pdksh print \ I was
} told).
zsh/ksh use the SysV definition of `echo' by default; bash uses the BSD
definition, it would appear. If one had RTM, one would have found that
`echo -E' does what you meant -- or else you can set the BSD_ECHO option
to get that behavior all the time.
So let's try the first example again with BSD_ECHO set:
schaefer[508] setopt BSD_ECHO
schaefer[509] echo "\\"
\
In this case it was double-quoted expansion that removed the backslash.
Using single quotes shows that it was not echo that removed it:
schaefer[513] echo '\\'
\\
Now back to the example:
schaefer[510] echo "\\" | read -r i; echo "$i"
\
schaefer[511] echo "\\\\\\\\"
\\\\
schaefer[512] echo "\\\\\\\\" | read -r i; echo "$i"
\\\\
Neither read nor echo has removed any backslashes. Only double-quoting
did so. Again trying the same thing with single quotes:
schaefer[514] echo '\\\\\\\\' | read -r i; echo "$i"
\\\\\\\\
This is all working exactly as documented.
--
Bart Schaefer Brass Lantern Enterprises
http://www.well.com/user/barts http://www.brasslantern.com
Zsh: http://www.zsh.org | PHPerl Project: http://phperl.sourceforge.net
prev parent reply other threads:[~2002-01-27 21:32 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-01-27 20:24 Clint Adams
2002-01-27 21:32 ` Bart Schaefer [this message]
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