Normally, pressing tab in a terminal window tells the terminal that you want to auto-complete a command, but pressing the ctrl+v combination beforehand will cause the tab character to be written out as you’d normally expect it to in a text editor. It’s handy to use grep to find a file when you use it to search through the output of the ls command as we showed in the first examples of the tutorial. Difference between find and grepįor those just starting out on the Linux command line, it’s important to remember that find and grep are two commands with two very different functions, even though we use both to “find” something that the user specifies. We mention this because files compressed with gzip are very commonly tar archives. Zgrep also works on tar files, but only seems to go as far as telling you whether or not it was able to find a match.
#Linux grep usage archive
It allows you to search the files inside of a compressed archive without having to first decompress that archive, basically saving you an extra step or two. You can use zgrep to search compressed files for a pattern. You could use this information to kill a running process or troubleshoot issues with the services running on your system. This is similar in function to just piping the output of the ‘ps’ command to grep. Here’s an example where we search a text document for a string. While you can use grep to search the output piped from other command-line tools, you can also use it to search documents directly. Grep will accept both single quotes and double quotes, so wrap your string of text with either. For example, what if we needed to search for the “My Documents” directory instead of the single-worded “Documents” directory? $ ls | grep 'My Documents' If you need to search for a string of text, rather than just a single word, you will need to wrap the string in quotes. So if grep returns nothing, that means that it couldn’t find the word you are searching for.
If the Documents folder didn’t exist, grep wouldn’t return any output. $ ls | grep DocumentsĪs you can see in the screenshot above, using the grep command saved us time by quickly isolating the word we searched for from the rest of the unnecessary output that the ls command produced. Let’s look in our home directory for a folder called Documents.Īnd now, let’s try checking the directory again, but this time using grep to check specifically for the Documents folder.
That’s something you would use the “ls” command for.īut, to make this whole process of checking the directory’s contents even faster, you can pipe the output of the ls command to the grep command. Say that you need to check the contents of a directory to see if a certain file exists there.
Let’s look at some really common examples. You can use it to search a file for a certain word or combination of words, or you can pipe the output of other Linux commands to grep, so grep can show you only the output that you need to see. Grep is a command-line tool that Linux users use to search for strings of text.
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