To exclude a single file called “vol-log-1.txt” we would use this command: grep -exclude=vol-log-1.txt 'sword' *.txt To do this, we will use the -exclude option. The word 'vorpal' didn't match anything, but 'sword' is included in the word 'password', so it was found several times in some pseudo log files. The results we want are masked by the deluge of fake results from other files that have the TXT extension. If we search for the word 'sword' with the same command structure, we get a lot of false positives. However, in this directory there are other TXT files, which have nothing to do with the poem. Note that the name of the file containing the corresponding line is displayed at the beginning of each line of output. grep 'vorpal' verse-1.txt verse-2.txt verse-3.txt verse-4.txt verse-5.txt verse-6.txt You can list each file on the command line, but with many files this approach doesn't scale. We can ask grep to search for a string or pattern in a collection of files. grep 'Jabberwock' jabberwocky.txt | grep -v 'slain'

We'll find all rows that contain the word 'Jabberwock' and then filter out all rows that also contain the word 'killed'. To see rows that contain a pattern but don't either, we can pipe grep in grep. This command will exclude all lines starting with any letter in the set of 'ACHT'. The command format is the same if you want to use a regex pattern instead of an explicit search index. We get exactly the same result as with the previous, longer command. grep -Ev 'Jabberwock|and' jabberwocky.txt If we use the -E (extended regular expressions), we can combine the search patterns with ' |', which in this context does not indicate a pipe, that is the logic OR operator. There is a corresponding drop in the number of rows in the output. grep -v -e 'Jabberwock' -e 'and' jabberwocky.txt We have to use it for every search template we use.

To achieve this, we will use the -e option (expression). Let's filter out all rows that contain 'Jabberwock' and all rows that contain 'and'. Lines that do not contain 'Jabberwock' are listed in the terminal window. This lists rows that do not match the search term. We can accomplish this with the -v (reverse correspondence). But what if we want to exclude rows containing the word “Jabberwock” and print the rest? Rows that contain matches with the search index are listed for us, with the corresponding item in each row highlighted in red. cat jabberwocky.txt | grep 'Jabberwock' grep 'Jabberwock' jabberwocky.text In both of these examples, we are looking for rows that match the search term “Jabberwock”. We use a short file that contains the text of the poem Jabberwocky, by Lewis Caroll. To search with grep you can direct the entry of another process there such as cat or you can supply a filename as the last command line parameter. You can tell it to ignore patterns, files, and directories so that grep completes its searches faster and you don't get swamped with meaningless false positives. Of course, there are ways to master grep. Sometimes it will search for files or directories that you'd rather not waste your time on, as the results may prevent you from seeing the wood for the trees. Grep is famously – perhaps, notoriously – thorough and determined. This represented goverall, concerningregular express search, pprint the corresponding lines. It takes its name from the g/re/p key sequence in the ed line editor (by the way, pronounced 'ee-dee'). it was developed in the early 1970s on Unix. These allow you to describe what you are looking for, rather than having to define it explicitly. The power of grep lies in its use of regular expressions. La grep The command searches text files for strings that match the search patterns you provide on the command line.

Grep exclude pattern