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(diff.info)Specified Folding

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Suppressing Lines Matching a Regular Expression
===============================================

   To ignore insertions and deletions of lines that match a regular
expression, use the `-I REGEXP' or `--ignore-matching-lines=REGEXP'
option.  You should escape regular expressions that contain shell
metacharacters to prevent the shell from expanding them.  For example,
`diff -I '^[0-9]'' ignores all changes to lines beginning with a digit.

   However, `-I' only ignores the insertion or deletion of lines that
contain the regular expression if every changed line in the hunk--every
insertion and every deletion--matches the regular expression.  In other
words, for each nonignorable change, `diff' prints the complete set of
changes in its vicinity, including the ignorable ones.

   You can specify more than one regular expression for lines to ignore
by using more than one `-I' option.  `diff' tries to match each line
against each regular expression, starting with the last one given.