From: Adam Bender <abender@...>
Date: 2009-04-30T13:27:58+09:00
Subject: Read and re-write file with one open?

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I would like to write a Ruby script that opens a text file, performs a gsub
on each line, and then overwrites the file with the updated contents.  Right
now I open the file twice: once to read and once to write.  The reason for
this is that if I try to perform both operations on the same IO object by
calling io.rewind and writing from the beginning, and the substituted word
is shorter than what it is replacing, some portion of the end of the
original file remains.  Is there an idiom for "clearing" the contents of the
file before writing?

Thanks,

Adam

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