What Is Grep?

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Searching for text in files is a pretty common thing to do. In Unix, there's a command line tool for that: GREP. GREP stands for Global regular expression and print. It's a management text search utility used in Unix. The "grep" command searches files or standard input for lines that match a given regular expression, then prints the matching lines to the program's standard output. The grep command can find strings in a file that match a given frequent phrase. It is part of the GNU Core Utilities or the "coreutils". The management takes one or more files as input and then searches through them for lines that contain a match. The grep command has many uses, but one of its most common uses is to search for specific text within a file. For example, if you want to search for all instances of the word "cat" in your document and print them out to your terminal window, you will type: You can use the grep command to search for text strings in files. It's pretty simple: Enter the command followed by the file you want to look at and then whatever string you want to search for. The general format is "grep [search-string] [filename].txt". For example, if you wanted to find lines containing the word "sat" in your file check.txt, you'd enter "grep sat check.txt" at your terminal. You can also abbreviate this as "grep sat check", which is easier to type but less precise in what it means. If there are multiple matches of your search term in a given line, it will display only one unless you use the "-o" option ("grep -o sat check"). This option tells you to grep not only to find all instances of your search term; it also prints them out in order (from first to last).

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