awk remove duplicate lines

Find the maximum and minimum of a function with three variables. I want to extract installed packages in a specific date to remove them easily. I use the following awk in order to remove duplicate lines from the /etc/fstab file on Linux. - [@hariharen9](https://github.com/hariharen9), - [@clevermiraz](https://github.com/clevermiraz), - [@smeubank](https://github.com/smeubank), - [@LJones95](https://github.com/LJones95), - [@shannon-nz](https://github.com/shannon-nz), - [@sammiepls](https://github.com/sammiepls), TIL: How to Watch YouTube Videos With mpv and Keyboard Shortcuts. It saves the first line as the header, and only prints the following lines if they are different from the saved header. I can list them in a line with the following command: cat /var/log/dpkg.log | awk '/ installed / && /2020-11-. 3. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. When practicing scales, is it fine to learn by reading off a scale book instead of concentrating on my keyboard? Modified 2 years, 6 months ago . but as you correctly point out this approach will remove all duplicate lines, not just the header line, and so it shouldn't be used. Why did Indiana Jones contradict himself? awk 'NR==1 && header=$0; $0!=header' originalfile > newfile. The awk command removes duplicate lines from whatever file is provided as an argument. How to add a specific page to the table of contents in LaTeX? I want to extract installed packages in a specific date to remove them easily. Why add an increment/decrement operator when compound assignments exist? So the action part defaults to simply printing the line for which the condition holds true. Avoid angular points while scaling radius. March 21, 2016. Why do complex numbers lend themselves to rotation? Exclude p=1 or set initial value of p to 0 to also remove starting blank lines. Learn more about Stack Overflow the company, and our products. Why do keywords have to be reserved words? To remove the duplicate lines while preserving their order in the file, use: awk '!visited [$0]++' your_file > deduplicated_file How it works The script keeps an associative array with indices equal to the unique lines of the file and values equal to their occurrences. All you have to do is check for an empty (really empty or just blank) line first. Note that this will omit printing the header if it is empty or can be parsed as the number 0. How much space did the 68000 registers take up? Is speaking the country's language fluently regarded favorably when applying for a Schengen visa? Indeed I tried adding an extra blank at the end and it was working, but was not satisfied with that 'solution'. Get Things Done Instead of Making Your Code Perfect, Clever Way to Remove Duplicate Lines With AWK. How to run a complex awk script on a remote machine? Do I have the right to limit a background check? so for example, I have an input file that looks like this: Sample Line 1 Sample line 2 Sample line 3 in the headers then they would be included in the output. If we are in the first line save the header and print it, then for each line we process if this is equal to the header skip it, otherwise print it. Then, a third file single3 can be produced with the awk command: single3 shall contain all single1 words, except for those mentioned in single2. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. @salom what terdon is saying is that the result is the same, whether you check and only de-duplicate if duplicate lines are present, or de-duplicate anyway. Thanks for the sed line. Why on earth are people paying for digital real estate? By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. How to add a specific page to the table of contents in LaTeX? Ubuntu and the circle of friends logo are trade marks of Canonical Limited and are used under licence. Removing duplicates in bash string using awk Ask Question Asked 5 years, 9 months ago Modified 4 years, 4 months ago Viewed 2k times 0 I was trying to apply the method proposed here { Removing duplicates on a variable without sorting } to remove duplicates in a string using awk when I noticed it was not working as expected. When practicing scales, is it fine to learn by reading off a scale book instead of concentrating on my keyboard? Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, The future of collective knowledge sharing, @Etan Reisner - this is exactly what I needed. I can list them in a line with the following command: But, as you notice some already installed packages are also listed since apt has to run some essential packages to configure the system. Sci-Fi Science: Ramifications of Photon-to-Axion Conversion, Defining states on von Neumann algebras from filters on the projection lattices, Can I still have hopes for an offer as a software developer. Making statements based on opinion; back them up with references or personal experience. The filtered lines are appended to the new file, after the header which was previously written there by tee. It can also shuffle the order of the lines for the same 4th field values which may not be desirable. Unix & Linux Stack Exchange is a question and answer site for users of Linux, FreeBSD and other Un*x-like operating systems. If and When can a Priest May Reveal Something from a Penitent's Confession? zz'" should open the file '/foo' at line 123 with the cursor centered, A sci-fi prison break movie where multiple people die while trying to break out, English equivalent for the Arabic saying: "A hungry man can't enjoy the beauty of the sunset", Avoid angular points while scaling radius, Morse theory on outer space via the lengths of finitely many conjugacy classes, Difference between "be no joke" and "no laughing matter". UNIX is a registered trademark of The Open Group. The best answers are voted up and rise to the top, Not the answer you're looking for? Why did Indiana Jones contradict himself? By clicking Post Your Answer, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct. Oh well. AWK: Extract lines with values that match and less than values in another file? Sci-Fi Science: Ramifications of Photon-to-Axion Conversion. rev2023.7.7.43526. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Connect and share knowledge within a single location that is structured and easy to search. What could cause the Nikon D7500 display to look like a cartoon/colour blocking? Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. rev2023.7.7.43526. You could also use grep after having skipped the first line: That assumes file.csv is a regular file (won't work with a pipe with most head implementation) and that head is POSIX compliant in that it will leave the cursor in stdin just after the first line. When practicing scales, is it fine to learn by reading off a scale book instead of concentrating on my keyboard? or if you don't mind an extra blank line at the end: This also works if the file has duplicate lines at beginning or end. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. It only takes a minute to sign up. Does every Banach space admit a continuous (not necessarily equivalent) strictly convex norm? Why add an increment/decrement operator when compound assignments exist. To skip all lines that are identical to the first one, you could do: To subscribe to this RSS feed, copy and paste this URL into your RSS reader. The best answers are voted up and rise to the top, Not the answer you're looking for? To subscribe to this RSS feed, copy and paste this URL into your RSS reader. To learn more, see our tips on writing great answers. What is the grammatical basis for understanding in Psalm 2:7 differently than Psalm 22:1? How my AWK code could be corrected supposed that further it should be piped to sort in other to sort the lines after the filtering of the repeats ? Connect and share knowledge within a single location that is structured and easy to search. Why do keywords have to be reserved words? Some sed implementations have the -i option to enable editing the file in place. Not the answer you're looking for? Asking for help, clarification, or responding to other answers. Miniseries involving virtual reality, warring secret societies. Identifying duplicate fields and REMOVE both with awk, completely ignore lines that start with a specific pattern. (Ep. Find centralized, trusted content and collaborate around the technologies you use most. Clever Way to Remove Duplicate Lines With AWK This snippet will remove duplicate lines: $ awk '!seen [$0]++' But how?! calculation of standard deviation of the mean changes from the p-value or z-value of the Wilcoxon test, A sci-fi prison break movie where multiple people die while trying to break out. The problem with your approach to using records is that when you set. awk remove duplicate words. ChatGPT) is banned, Testing native, sponsored banner ads on Stack Overflow (starting July 6), Awk: Remove duplicate lines with conditions, Remove duplicate based on condition awk/bash, Removing all occurences of duplicates in a file on Unix, Removing duplicates in bash string using awk, Eliminate Duplicate Rows based on Two Columns using Awk, shell awk script to remove duplicate lines. Tell AWK to accept lines starting with # as well as non-duplicate lines: If you want to avoid doing this if there are no duplicate lines (per your comments), you can use something like. Names are not sorted alphabetically. Stack Exchange network consists of 182 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. Find centralized, trusted content and collaborate around the technologies you use most. What could cause the Nikon D7500 display to look like a cartoon/colour blocking? The same approach but in the stream editor utility sed: This is using a shell that has process substitutions (<()), like bash or zsh, to get the header line from the file using head, write that to a new file with tee, and then filter out all header lines from the original file using grep. The issue is clear now. By the way, it will be easier to help if you produce a minimal, complete example. Links awk The GNU Awk User's Guide Avoid angular points while scaling radius, A sci-fi prison break movie where multiple people die while trying to break out. so for example, I have an input file that looks like this: and the output would then turn all multiple blank lines into a singular one, so the output file would look like this: I've been able to complete this with a sed command, but the problem insists that I use awk in order to obtain this output. Not the answer you're looking for? How can I remove a mystery pipe in basement wall and floor? Is there a distinction between the diminutive suffixes -l and -chen? Im not proficient in using awk, but Ive found useful one-liners that do what I want. Accidentally put regular gas in Infiniti G37. Luckily I can differentiate those packages via. Thanks! rev2023.7.7.43526. without to create new file , like verification before I change the fstab file, sorry maybe I not explained enough , what I mean is that awk need to return the numbers of duplicate line's from the file not only display them , and only if number isnt equal to 0 then activate the awk '/^#/ || !a[$0]++' /etc/fstab. How can I change the awk syntax in order to ignore lines starting with # in the file? Why did the Apple III have more heating problems than the Altair? Removing duplicate lines from a text file using Linux command line here is my CSV contained repeats of the first line: To post-process this CSV I need to remove repetitions of the header line, keeping the header only in the begining of the fused csv (on the first line! Ask Question Asked 2 years, 6 months ago. Then, a third file file3 can be produced with the awk command: file3 shall contain all file1 words, except for those mentioned in file2. The files are: This gives me the same as the original, like this: For anyone less knowledgeable about AWK, a more elaborate and programmatic solution is: The BEGIN block run before starting to read the input file "new.csv" reads the entire key file "remove.txt" into an associative array with keys as the remove keys. "vim /foo:123 -c 'normal! Customizing a Basic List of Figures Display, English equivalent for the Arabic saying: "A hungry man can't enjoy the beauty of the sunset". Aren't all the listed packages installed, as per your first statement? In this case, we don't have any reference, assignment to a[$0] if it existed. Find centralized, trusted content and collaborate around the technologies you use most. thank you very much again! (Ep. 2 I use the following awk in order to remove duplicate lines from the /etc/fstab file on Linux. I needed a simple way to remove all duplicates lines from the file without sorting the lines. I do not understand why there is this character and where does it come from? Is a dropper post a good solution for sharing a bike between two riders? How can I change the awk syntax in order to ignore lines starting with # in the file? Can you work in physics research with a data science degree? Vivek Gite. However, following this method I get this. Now. If you want to save the output to a file instead of displaying it, make it look like this: #!/bin/bash. What is the Modified Apollo option for a potential LEO transport? 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