linux find

Find if a string exists in all files under a directory: find .|xargs grep -ri "IBM" Find if a string exists in all files under a directory, and only print the filenames: find .|xargs grep -ri "IBM" -l

Regular Expressions (1) Regular expressions are generally used to describe special text patterns, consisting of ordinary characters (e.g., a-z) and special characters (called metacharacters, such as /, *, ? etc.). (2) Basic Metacharacter Set and Their Meanings ^: Matches only the beginning of a line. E.g., ^a matches lines starting with 'a' like abc, a2e, a12, aaa, etc. $: Matches only the end of a line. E.g., a$ matches lines ending with 'a' like bca, 12a, aaa, etc. \*: Matches zero or more occurrences of the preceding single character. E.g., (a)* matches empty string, a, aa, aaa, etc. []: Matches only characters within []. It can be a single character or a