Manipulation of text by programs, scripts, etc.

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How can I delete all text between nested curly brackets in a multiline text file?

This question comes from How can I delete all text between curly brackets in a multiline text file? (just the same, but without the requirements for nesting). Example: This is { {the multiline ...
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votes
4answers
20k views

How to use bash script to read binary file content?

I want to read a character and then a fixed length of string (the string is not null terminated in the file, and its length is given by the preceding character). How can I do this in a bash script? ...
8
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2answers
3k views

How can I use column to delimit on tabs and not spaces?

I'd like to use Unix column to format some text. I have fields delimited by tabs, but within each field there are also spaces. column delimits on white space (tabs and spaces). How can I make column ...
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3answers
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How do I make python programs behave like proper unix tools?

I have a few Python scripts laying around, and I'm working on rewriting them. I have the same problem with all of them. It's not obvious to me how to write the programs so that they behave like ...
8
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1answer
182 views

Filter the clipboard content without using an intermediate file

I'm trying to modify the text that is in my clipboard, remove certain lines of that contains some strings and then get the output for further manipulation (I prefer coping to my clipboard only if I ...
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4answers
5k views

Concatenate lines by first column by awk or sed

How can I use awk in the following situation? I want to concatenate lines that start with the same column. Only the first column is kept after the join (in this case aaa, www, hhh). The file may be ...
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3answers
7k views

How do I grep without leading whitespaces?

I'm greping through a large codebase, and leading whitespaces and tabulation seem to be quite annoying. Is there any way to get rid of it? grep -R "something" ./ E.g, instead of: foo/bar.cpp: ...
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2answers
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Deleting all C comments with sed

I am trying to write a script that will delete all comments and everything in between inside C files in my current directory. I've been using sed, and this is what I have so far: sed -i '/ * [^()] ...
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1answer
3k views

How to remove duplicate lines in a large multi-GB textfile?

My question is similar to this question but with a couple of different constraints: I have a large \n delimited wordlist -- one word per line. Size of files range from 2GB to as large as 10GB. I ...
8
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1answer
809 views

How can I write a new syntax highlighter for gedit?

Some times I wish the particular language I happen to be writing in had syntax highlighting. How can I add that?
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3answers
2k views

How do I take a list and remove it from a file?

I have a long list of domain names that I need to remove from /etc/remotedomains. They're probably not in any particular order in the file. Each domain is on one line. How could I iterate through the ...
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5answers
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`highlight` command

Is there a command which can be used to easily highlight (with colors, bold text or inverted back-/foreground) specific strings in stdin while passing the entire string to stdout? I'm thinking of ...
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2answers
2k views

How could I use Bash to find 2 bytes in a binary file, increase their values, and replace?

I'm trying to find two bytes inside binary file, then increase value of those two bytes and replace them inside file. Those two bytes are on positions 0x82-0x83. For now on I have successfully ...
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4answers
1k views

Creating a single output stream out of three other streams produced in parallel

I have three kinds of data that are in different formats; for each data type, there is a Python script that transforms it into a single unified format. This Python script is slow and CPU-bound (to a ...
8
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3answers
2k views

Is it possible to nest a 'find -exec' within another 'find -exec'?

Something like the following is what I what I'm after, but my code doesn't work, no matter how I escape {} and + ; find ./ -maxdepth 1 -type d -name '.*' -exec \ find {} -maxdepth 1 -type f ...
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2answers
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Parsing XML, JSON, and newer data file formats in UNIX using command line utilities

The Unix environment has some excellent tools for parsing text in various forms. However, of late, the data is not in the traditional (historical) formats (CSV, TSV, record-based or some other ...
8
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1answer
448 views

Is there a way to make perl -i not clobber symlinks?

A friend of mine points out that if you do: perl -pi.bak -e 's/foo/bar/' somefile when "somefile" is actually a symlink, perl does just what the docs say it will do: It does this by renaming ...
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7answers
826 views

Slick one-liner to convert a list like “1: 2, 3, 4, 5” to “1.2, 1.3, 1.4, 1.5”

Let's say I have a file that looks something like this: 23: a, b, c, d 24: b, d, f 25: c, g and I want to get output like this: 23.a 23.b 23.c 23.d 24.b 24.d 24.f 25.c 25.g Of course it's not ...
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5answers
692 views

Modify a file without creating another file

Is there a way to modify a file without writing the contents to another file, without sed and awk? For example: $ cat test.txt aaa aaa bbb ccc ddd Replacing using sed with -i option, sed -i ...
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7answers
12k views

How to test whether the file is crlf or lf without modyfing it?

I need to periodically run a command, that ensures that some text files are kept in linux mode. Unfortunately dos2unix always modifies file, which would mess file's and folder's timestamp and cause ...
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10answers
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What's a good way to filter a text file to remove empty lines?

I have a .csv file (on a mac) that has a bunch of empty lines, e.g.: "1", "2", "lorem ipsum lorem ipsum lorem ipsum lorem ipsum lorem ipsum lorem ipsum lorem ipsum lorem ipsum lorem ipsum lorem ipsum ...
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2answers
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How can I cut a large file in place? [duplicate]

I have a very big text file, about 80GB, and I need to cut a part form it that lies between two given lines. The part I need is not big, and I have not enough space left on the hard drive to do things ...
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5answers
11k views

Transposing rows and columns

I have a file with the lines like below. title1:A1 title2:A2 title3:A3 title4:A4 title5:A5 title1:B1 title2:B2 title3:B3 title4:B4 title5:B5 title1:C1 title2:C2 title3:C3 title4:C4 title5:C5 ...
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4answers
29k views

Remove last character from line

I want to remove last character from a line: [root@ozzesh ~]#df -h | awk '{ print $5 }' Use% 22% 1% 1% 59% 51% 63% 5% Expected result: Use 22 1 1 59 51 63 5
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5answers
468 views

List out strings which are substrings of other strings in the list

I have a list of names like so: dog_bone dog_collar dragon cool_dragon lion lion_trainer dog I need to extract out names that appear in other names like so: dragon lion dog I looked through the ...
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4answers
280 views

How to grep-inverse-match and exclude “before” and “after” lines

Consider a text file with the following entries: aaa bbb ccc ddd eee fff ggg hhh iii Given a pattern (e.g. fff), I would like to grep the file above to get in the output: all_lines except ...
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6answers
617 views

Obtain values of a section of a file

I have a configuration file in the following format. <Title> [part1] A.File = a A.Val = val1 B.File = a B.Val = val1 [part2] A.File = a1 A.Val = val2 B.File = a B.Val = val1 ...
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5answers
1k views

Joining two files with unique identifier

I have two files with approximately 12900 and 4400 entries respectively, that I want to join. The files contain location information for all landbased weather observing stations around the globe. The ...
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7answers
345 views

Removing numeric values in certain columns whilst keeping minus signs?

I put my hands up to being a complete beginner, so apologies if I'm doing this wrong. Say I have the following data frame that continues indefinitely horizontally and vertically with negative numbers ...
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4answers
300 views

Need to move the last line of the file to second line of the same file

I have a file 'test' in linux with below data. aaaaaa bbbbbb cccccc dddddd eeeeee I need to cut the last line of this file and put it in the second position. It must look like below. aaaaaa eeeeee ...
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7answers
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How to insert the content of a file into another file before a pattern (marker)?

File1 contents: line1-file1 "1" line2-file1 "2" line3-file1 "3" line4-file1 "4" File2 contents: line1-file2 "25" line2-file2 "24" Pointer-file2 "23" ...
7
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2answers
4k views

A shell script for joining two files

I want to write a shell script that get two files A and B, and get a result like this: File A: user_a tel_a addr_a user_b tel_b addr_b File B: process_1 user_a process_2 user_a process_3 user_b ...
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4answers
363 views

Sort fields inline

I'm trying to sort within a line of input over an unknown number of fields: Input: ab bc bc ab cd ef bc bc cd ef cd bc ab ef ab bc cd gh Output: ab bc ab bc bc cd ef bc cd ef ab cb cd ab bc cd ...
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4answers
6k views

Is it possible in bash, to start reading a file from an arbitary byte count offset?

I want to locate a date which is somewhere in an 8 GB log (text). Can I somewhat bypass a full sequential read, and first do binary splits of the file (size), or somehow navigating the filesystem ...
7
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2answers
2k views

In `while IFS= read..`, why does IFS have no effect?

I might have something absolutely wrong, but it looks convincing to me, that setting IFS as one of the commands in the pre-do/done list has absolutely no effect. The outer IFS (outside the while ...
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2answers
1k views

How to do a text replacement in a big folder hierarchy?

I want to search and replace some text in a large set of files excluding some instances. For each line, I want a prompt asking me if I need to replace that line or not. Something similar to vim's ...
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4answers
335 views

Getting text from last marker to EOF in POSIX.2

I have a text with marker lines like: aaa --- bbb --- ccc I need to get a text from the last marker (not inclusive) to EOF. In this case it will be ccc Is there an elegant way within POSIX.2? ...
7
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4answers
297 views

Groupwise uniq command?

I am searching for a command to get from a file in this format: hello 32 hello 67 hi 2 ho 1212 ho 1390 ho 3000 To this format (deduplicate by taking the last row of a "group"): hello ...
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7answers
2k views

How to sort (by whatever key) BibTex entries in `.bib` file?

I work with LaTeX and do versioning with Git. For bibliography management I use Mendeley. The problem is that each time Mendeley synchronizes it's .bib exports, they are in different order, what ...
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4answers
150 views

Split an input for different command and combine the result

I know how to combine the result of different command paste -t',' <(commanda) <(commandb) I know pipe same input to different command cat myfile | tee >(commanda) >(commandb) Now ...
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4answers
3k views

tail -f, but with line numbers

I'm trying to see how many times foo bar appears in /var/log/foo.log within an arbitrary amount of time on a remote server, but nothing that I've tried so far has worked. I've already got a timer ...
7
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6answers
184 views

How to efficiently split up a large text file wihout splitting multiline records?

I have a big text file (~50Gb when gz'ed). The file contains 4*N lines or N records; that is every record consists of 4 lines. I would like to split this file into 4 smaller files each sized roughly ...
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5answers
608 views

How intelligent are unix utilities?

Unix utilities like sort, find, grep, diff et al are very handy to perform quick tasks, sometimes without writing any code at all. I wanted to know what algorithms do they internally use and how do ...
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1answer
3k views

How to merge two files in corresponding row?

Now,I have two files: aaaa.txt: a=0; b=1; c=2; bbbb.txt: d=3 e=4 f=5 I want to merge aaaa.txt and bbbb.txt to cccc.txt. cccc.txt as follow: a=0;d=3 b=1;e=4 c=2;f=5 So, what can I do ...
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2answers
8k views

How to find difference between two timestamps up to milliseconds?

I am new to shell scripting. The heart of my script is to find the difference between two timestamps up to milliseconds. With me I have a file with content of timestamps only as 2012-09-13 ...
7
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2answers
790 views

What governs the limits of shell brace expansion?

In this example I refer to the expansion of a sequence of integers, but perhaps(?) the limits would be relevant to all aspects of brace expansion.. This more general view is also of interest to me. ...
7
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1answer
326 views

Change date “July 29th, 2011” to “20110729”

I have lots of HTML files contains date with format July 29th, 2011 I want to change date format July 29th, 2011 to 20110729, December 9th, 2010 to 20101209, etc. I think sed may works but still ...
7
votes
1answer
79 views

How to display the non-sparse parts of a sparse file?

Imagine a file created with: truncate -s1T file echo test >> file truncate -s2T file I now have a 2 tebibyte file (that occupies 4kiB on disk), with "test\n" written in the middle. How would ...
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2answers
149 views

How does one find and replace text in all open files with jed?

How does one find and replace text in all open files with jed?
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2answers
472 views

Strip // Comments From Files

What's the best way to strip all code comments in a given directory? I'd like to strip out all // ... EOL comments, and /* blah \*/ (or /** ... \*/) comments as well. This is a PHP project, and I'd ...