1.
grep
's Regular Expression Metacharacters(Which I always dismissed~)
Option
What It Does
| [^] | Matches one character not in the set | '[^A–K]ove' | Matches lines not containing a character in the range A through K, followed by ove. |
| \< | Beginning-of-word anchor | '\<love' | Matches lines containing a word that begins with love. |
| \> | End-of-word anchor | 'love\>' | Matches lines containing a word that ends with love. |
| \(..\) | Tags matched characters | '\(love\)ing' | Tags marked portion in a register to be remembered later as number 1. To reference later, use \ 1 to repeat the pattern. May use up to nine tags, starting with the first tag at the left-most part of the pattern. For example, the pattern love is saved in register 1 to be referenced later as \ 1. |
| x\{m\} x\{m,\} x\{m,n\} [a] | Repetition of character x: m times, at least m times, or between m and n times | 'o\{5\}' 'o\{5,\}' 'o\{5,10\}' | Matches if line has 5 occurences of o , at least 5 occurences of o , or between 5 and 10 occurrences of o . |
EXPLANATION
Prints the line if it contains the word north. The \< is the beginning-of-word anchor, and the \> is the end-of-word anchor.
4. grep 's Options| –b | Precedes each line by the block number on which it was found. This is sometimes useful in locating disk block numbers by context. |
| –c | Displays a count of matching lines rather than displaying the lines that match. |
| –h | Does not display filenames. |
| –i | Ignores the case of letters in making comparisons (i.e., upper-- and lowercase are considered identical). |
| –l | Lists only the names of files with matching lines (once), separated by newline characters. |
| –n | Precedes each line by its relative line number in the file. |
| –s | Works silently, that is, displays nothing except error messages. This is useful for checking the exit status. |
| –v | Inverts the search to display only lines that do not match. |
| –w |
Searches for the expression as a word, as if surrounded by
\<
and
\>.
This applies to
grep
only. (Not all versions of
grep
support this feature; e.g., SCO UNIX does not.)
|
