Grep Command example in Unix/Linux

Here are some of the frequently used grep command in unix/Linux with examples:

1. Search a given string in a file

grep "search_string" file_name

2. Search a specific string in multiple files by providing the file name pattern

grep "search_string" file_name_pattern

e.g.: grep "name" class*.txt

3. Case insensitive search

grep -i "search_string" file_name

e.g.
Both commands would return same result

grep -i "name" class1.txt
grep -i "NAME" class1.txt

4. Invert match

grep -v "101" class1.txt

Above command would return all the rows that doesn't contain the string "101".

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