Grep is a command, first developed for the Unix operating system, which works with all systems that are similar to this one. This command searches files for matching lines and displays the lines containing the phrases you are searching for. The sequence of characters is matched regardless of word boundaries. Also, the sequence of characters that make up the search words are case sensitive, but people should keep in mind that there is an option for case-insensitive searches.
For example, if you are searching for the word “apple”, you will get lines, containing “apples” or “pineapple”, but not lines, containing “Apple”. You will get lines, containing “Apple” only if you have chosen the option for case-insensitive searches.
As to the syntax information of the grep command, it is as follows:
grep [OPTIONS] PATTERN [FILE…]
The arguments that are not in brackets are obligatory, whereas the ones that are in square brackets, namely Options and File, are optional.
grep -v option
This command can be used, if you want to find a relevant word and exclude an irrelevant one.
grep -c option
This option will come handy in case you want to count the number of times a particular word is used.
grep -i option
It is an option for case insensitive searches, so using it, you will be able to find words, written not only in small letters, but also in capitals or in small letters with an initial capital letter.
grep -w option
This command can be used, if you want to find whole words and not just patterns.
grep -l option
Use this option when you want to see the file names, but you don’t want to see the matched lines.
egrep
It stands for extended grep. By using “|” you can search for either one thing or another thing.
Windows Grep
In Windows the same function is performed by a search tool, known as Windows Grep. It is used not only for searching files on your computer, but also for replacement in those files. Windows Grep is compatible with Windows 2000, Windows XP, Windows 7, and Vista. It can search RTF, HTML, spreadsheets, word processor documents, etc.
SeekFast
The programme SeekFast can be used as a substitute for the grep command in Unix and Windows Grep in Windows. It will be useful to people who want to search folders and subfolders on their computer for a given word or phrase. This software allows you to locate the file/files, in which the word or phrase is used, but it also makes it possible with a single click of the mouse to view the context in which the search terms are used or to open the respective file/files. Moreover, searches can be case-sensitive or case-insensitive – you can change the settings, depending on your needs in a given situation. And you can use this program for searching different types of files: Microsoft Word documents, PDF files, text files, and rich text format files.