If you have any questions or feedback, feel free to leave a comment. The grep command allows you to exclude patterns and directories when searching files. To exclude multiple directories, enclose the excluded directories in curly brackets and separate them with commas with no spaces.įor example, to find files that contain the string ‘gnu’ in your Linux system excluding the proc, boot, and sys directories you would run: grep -r -exclude-dir= linuxize * Conclusion #
Grep unique how to#
Here is an example showing how to search for the string linuxize in all files inside the /etc, excluding the /etc/pki directory: grep -R -exclude-dir=pki linuxize /etc The path to the excluded directory is relative to the search directory. To exclude a directory from the search, use the -exclude-dir option. The main difference between -r or -R options is that when grep is invoked with uppercase R it will follow all symbolic links Check out man uniq: -u Only output lines that are not repeated in the input. Sometimes when performing a recursive search with the -r or -R options, you may want to exclude specific directories from the search result. In the following example, the lines where the string games occur at the very beginning of a line are excluded: grep -v "^games" file.txtĪ command’s output can be filtered with grep through piping, and only the lines matching a given pattern will be printed on the terminal.įor example, to print out all running processes on your system except those running as user “root” you can filter the output of the psĬommand: ps -ef | grep -wv root Exclude Directories and Files # You can specify different possible matches that can be literal strings or expression sets. If you use the extended regular expression option -E, then the operator | should not be escaped, as shown below: grep -Ewv 'nologin|bash' /etc/passwd By default, grep interprets the pattern as a basic regular expression where the meta-characters such as | lose their special meaning, and you must use their backslashed versions. GNU grep supports three regular expression syntaxes, Basic, Extended, and Perl-compatible. The following example prints the lines that do not contain the strings nologin or bash: grep -wv 'nologin\|bash' /etc/passwd You can use the -e option as many times as you need.Īnother option to exclude multiple search patterns is to join the patterns using the OR operator |. To specify two or more search patterns, use the -e option: grep -wv -e nologin -e bash /etc/passwd If the search string includes spaces, you need to enclose it in single or double quotation marks. To ignore the case when searching, invoke grep with the -i option. This means that the uppercase and lowercase characters are treated as distinct. I haven’t found anything in the standard library that lets me avoid the copy, so I had to resort to writing my own split function.The -w option tells grep to return only those lines where the specified string is a whole word (enclosed by non-word characters).īy default, grep is case-sensitive.
Grep unique code#
Keen eyes will spot that our code is still doing unnecessary work - copying the current line from BufRead into the line buffer. The sort command orders a list of items both alphabetically and numerically, whereas the uniq command removes adjacent duplicate lines in a list. fn uniq_cmd(delim: u8) -> Result Going zero-copy My initial implementation was very simple I used clap to parse command line arguments, anyhow to handle errors (actually I used failure, but that was later replaced), and wrote the simplest implementation I could think of for uniq ( source). In this blog post, we’ll look at how to implement and optimize the first mode. huniq implements two modes it removes duplicates and counts them. That’s why I created huniq in order to count/remove duplicates by using a hash table. A more speedy way to get this job done might be to use a hash table. You might notice, that for the purpose above, sorting is not really required.
Grep unique download#
The first two commands download the blog, the third removes all special characters and splits lines into words, grep gets rid of any empty lines left over, sort|uniq -c counts duplicates, and the final sort -n ranks them. Unsurprisingly, I use ‘the,’ ‘to,’ and ‘a,’ quite a lot. For example, looking below, you could create a ranking of the words I use most often in this blog: $ curl " " | html2text2 | sed | grep -v '^\s*$' | sort | uniq -c | sort -n 34 s 39 com 39 tag 40 it 40 that 48 you 49 is 52 in 53 search 82 of 88 I 94 and 112 a 114 to 180 the Personally, I use this quite often to create a ranking of something. Sort | uniq sorts data given to it via stdin and then removes any duplicates. Filtering Duplicates on the Command Line: 30x Faster than sort|uniq
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