The above command will try to find a string “func main()” in all the files in a particular directory and also in the subdirectories as well. In the above command replace the “word” placeholder withįor that we make use of the command shown below − grep -rni "func main()" * Now, let’s consider a case where we want to find a particular pattern in all the files in a particular directory, say dir1. v : It prints out all the lines that do not match the pattern n : Display the matched lines and their line numbers. While there are plenty of different options available to us, some of the most used are − -c : It lists only a count of the lines that match a pattern Normally, the pattern that we are trying to search in the file is referred to as the regular expression. So its worth nothing that the default nature of grep is case. It is one of the most used Linux utility commands to display the lines that contain the pattern that we are trying to search. The -0 option (or -null on some systems) corresponds to the -print0 option of find.The grep command in Linux is used to filter searches in a file for a particular pattern of characters.
So, replacing the find command above with the locate almost-equivalent: $ locate '*.txt' -0 | xargs -0 fgrep texthere The database does only contain files in directories accessible by all users, so if you have removed the read-permissions on your own directories, your files won't be there. The locate command doesn't search the file hierarchy but instead uses a database (which is usually updated daily, so not all files may be there). but I would generally advise against that because people have a tendency to mess up their systems by forgetting they are root.ĪNOTHER SOLUTION would be to use the locate command to locate all the. Or you could just sudo -s to get a root shell and run the thing from there. Or you could try to craft another -perm flag for find (and also get it to ignore directories that you can't enter), but that would be too time consuming and result in a ridiculously long command line, so I won't do that here. You can either run find and fgrep with sudo prepended to them: $ sudo find. Obviously there will be files that you aren't able to read. So, if you have a plain text string and you want to look for it in every single file on the whole system: $ find / -type f \! -perm -o=x -name "*.txt" -print0 | xargs -0 fgrep texthere This is a utility which is exactly equivalent to grep -F that you should use if your search string is a plain text string with no regular expressions in it. It's because you're not using those two option that I believe you get those "no such file or directory" errors.
And the corresponding option to xargs for receiving these as nul-delimited file names is -0. This ( -print0) means each file name will be delimited by a nul character ( \0) rather than a space character. To be able to pass these properly between find and grep we do $ find / -type f \! -perm -o=x -name "*.txt" -print0 | xargs -0 grep texthere
Some file names might have spaces in them, or other wonky character that we usually don't want in file names. To use grep to search for words in a file, type grep, the word or words you want to search for, the files you want to look in, and pressOne is a safety thing, and the other may possibly improve speed a tiny bit. Now, there's a couple of more things we can do. I'm also specifying that I want files ( -type f) that are not executable ( \! -perm -o=x) (the ! needs to be escaped so that your shell doesn't do funny things with it). with / here, because that's where I think you are (correct me if I'm wrong). Since it looks like you're only interested in plain text files, we can exclude any other type of file (executables): $ find / -type f \! -perm -o=x -name "*.txt" | xargs grep texthere You can use find to narrow down the amount of files to look at.Īt the moment, you have $ find.
It's just an awful lot of files to search. It will take a long time no matter what you do. If you want to search absolutely all files on the whole system, than what you're doing is pretty much right. But since you say it takes an awfully long time, I'm leaning more towards the first assumption (the root directory).
If you're getting errors about permissions (you don't say you do), then I'm guessing you're standing in either the root directory ( /) or in some path where you don't have permission to read all files, such as in /etc or in /var.
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