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--- linux_wiki:use_grep_and_regular_expressions_to_analyze_text [2016/02/28 22:49]
billdozor created
+++ linux_wiki:use_grep_and_regular_expressions_to_analyze_text [2019/05/25 23:50]
@@ Line 1: / Line 1: @@
-====== Use Grep And Regular Expressions To Analyze Text ======
-**General Information**
-About this page/how-to/script.
-----
-Filter lines that start with (^) a comment (#) in myfile.txt
-<code bash>
-grep "^#" myfile.txt
-</code>
-Filter for "auth", ignore case
-<code bash>
-grep -i "auth" /etc/ssh/ssh_config
-</code>
-Common Grep Options
-  * -i => ignore case
-  * -v => invert match (show non-matching lines)
-  * -c => output the count of matches (or count of non-matching if used with -v)
-  * -o => print only the matched parts of the matching line
-  * -n => prefix each line of output with the line number
-Regular Expression Matching
-  * ^ => starts with
-  * $ => ends with
-  * [ab] => match a or b
-  * [^ab] => do not match a or b
-  * ? => previous item optional (match 0 or 1 time)
-  * * => previous item matched zero or more times
-  * + => previous item matched one or more times
-  * . => match any single character (the period)
-  * {x} => previous item matched exactly x times
-  * {x,} => previous item matched x or more times
-  * {,y} => previous item matched at max y times
-  * {x,y} => previous item matched at least x times, but not more than y times
-----