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Post Closed as "Duplicate" by Kusalananda♦, CommunityBot, Jeff Schaller♦, Stephen Kitt, Romeo Ninov
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Stephen Kitt
Stephen Kitt
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I am getting the hang of grep and regex, but I am confused about the different options.

grep --help | grep -i "reg.*ex"
  -E, --extended-regexp     PATTERN is an extended regular expression (ERE)
  -G, --basic-regexp        PATTERN is a basic regular expression (BRE)
  -P, --perl-regexp         PATTERN is a Perl regular expression

I have a general knowledge of regular expressions, but often I find myself stumbling on the basics (e.g. Using '*' when it actually requires '' when it actually requires '.'.*'), which I blame on not knowing the differences between the types of regular expressions (ERE, BRE, Perl regex).

Is it explained somewhere in detail?

I am getting the hang of grep and regex, but I am confused about the different options.

grep --help | grep -i "reg.*ex"
  -E, --extended-regexp     PATTERN is an extended regular expression (ERE)
  -G, --basic-regexp        PATTERN is a basic regular expression (BRE)
  -P, --perl-regexp         PATTERN is a Perl regular expression

I have a general knowledge of regular expressions, but often I find myself stumbling on the basics (e.g. Using '' when it actually requires '.'), which I blame on not knowing the differences between the types of regular expressions (ERE, BRE, Perl regex).

Is it explained somewhere in detail?

I am getting the hang of grep and regex, but I am confused about the different options.

grep --help | grep -i "reg.*ex"
  -E, --extended-regexp     PATTERN is an extended regular expression (ERE)
  -G, --basic-regexp        PATTERN is a basic regular expression (BRE)
  -P, --perl-regexp         PATTERN is a Perl regular expression

I have a general knowledge of regular expressions, but often I find myself stumbling on the basics (e.g. Using '*' when it actually requires '.*'), which I blame on not knowing the differences between the types of regular expressions (ERE, BRE, Perl regex).

Is it explained somewhere in detail?

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Calculus Knight
Calculus Knight
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Grep options for Regular Expressions. (ERE, BRE, Perl regex) differences

I am getting the hang of grep and regex, but I am confused about the different options.

grep --help | grep -i "reg.*ex"
  -E, --extended-regexp     PATTERN is an extended regular expression (ERE)
  -G, --basic-regexp        PATTERN is a basic regular expression (BRE)
  -P, --perl-regexp         PATTERN is a Perl regular expression

I have a general knowledge of regular expressions, but often I find myself stumbling on the basics (e.g. Using '' when it actually requires '.'), which I blame on not knowing the differences between the types of regular expressions (ERE, BRE, Perl regex).

Is it explained somewhere in detail?