Unix command for searching a string in a file

For more, consult the Unix manual page by entering at the Unix prompt:. This is document admm in the Knowledge Base. Last modified on Skip to: content search login. Knowledge Base Toggle local menu Menus About the team. Knowledge Base Search. Log in. Options Help Chat with a consultant.

Include archived documents. Note: A line does not represent a line of text as viewed on the terminal screen. A line in a text file is a sequence of characters until a line break is introduced.

The output of grep commands may contain whole paragraphs unless the search options are refined. Grep is an acronym that stands for G lobal R egular E xpression P rint. The text search pattern is called a regular expression.

When it finds a match, it prints the line with the result. The grep command is handy when searching through large log files. The grep command consists of three parts in its most basic form. The first part starts with grep , followed by the pattern that you are searching for. After the string comes the file name that the grep searches through.

The command can contain many options, pattern variations, and file names. Combine as many options as necessary to get the results you need. Below are the most common grep commands with examples.

Note: Grep is case-sensitive. Make sure to use the correct case when running grep commands. To print any line from a file that contains a specific pattern of characters, in our case phoenix in the file sample2 , run the command:. Grep will display every line where there is a match for the word phoenix. When executing this command, you do not get exact matches.

Instead, the terminal prints the lines with words containing the string of characters you entered. Here is an example:. Tip: If your search pattern includes characters other than alphanumeric, use quotation marks.

This includes blank spaces or any symbol. To search multiple files with the grep command, insert the filenames you want to search, separated with a space character. In our case, the grep command to match the word phoenix in three files sample , sample2 , and sample3 looks like this example:. The terminal prints the name of every file that contains the matching lines, and the actual lines that include the required string of characters. You can append as many filenames as needed.

All rights reserved Terms of Service. When an application is deployed, mostly only the binary files are packaged. Example 1. Display printable characters from an object file Let us create a sample object file of a C code as shown below. Unlike grep command, strings command will list all the printable characters from binary file. Shantanu Oak November 2, , am.

Chris F. Johnson November 13, , am. Really this is very useful article for me. Thanks lot. Mike Myers June 17, , am. Those offsets in example 4 are decimal, not octal. I will be posting instruction guides, how-to, troubleshooting tips and tricks on Linux, database, hardware, security and web.