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What language or text editor are you using to accomplish this? Also, how long is the &quot;certain string&quot;?
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What language or text editor are you using to accomplish this? Also, how long is the "certain string"?

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I am using notepad ++, the string is only 5 characters long.<br />
So every line that begins with &lt;213&gt; I need to trim to 72 characters.
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I am using notepad ++, the string is only 5 characters long.
So every line that begins with <213> I need to trim to 72 characters.

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That did the trick! &nbsp;Thank you!
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I have been playing with regex but havent had any luck. &nbsp;Any ideas?
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I have been playing with regex but havent had any luck.  Any ideas?

I have a large text file, I need to trim every line that begins with a certain string down to 72 characters.

A regular expression ("regex") is a sequence of characters that define a search pattern, mainly for use in pattern matching with strings, or string matching, i.e. "find and replace"-like operations. Regular expression processors are found in several search engines, search and replace dialogs of several word processors and text editors, and in the command lines of text processing utilities, such as sed and AWK. Many programming languages provide regular expression capabilities, some built-in, for example Perl, JavaScript, Ruby, AWK, and Tcl, and others via a standard library, for example .NET languages, Java, Python and C++ (since C++11). Most other languages offer regular expressions via a library.