in reply to break up file with no line breaks

Try this, it'll take around 10 seconds: 

perl -ple"BEGIN{ $/ = \80 }" theBigFile > theNewFile

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If you only want to break lines after a comma, then it's a tad more complicated:

(Note:one-liner wrapped for posting!) 

perl -e"BEGIN{$/=\80}" 
-nle"$x.=$_; print $1 while length($x)>80 and $x=~s[(.{1,80},)(?!,)][]
+"
 theBigFile > theNewFile

[download]
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