Comparing two files in linux terminal

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Top 5 Answer for Comparing two files in linux terminal

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if you have vim installed,try this:

vimdiff file1 file2 


vim -d file1 file2 

you will find it fantastic.enter image description here

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Sort them and use comm:

comm -23 <(sort a.txt) <(sort b.txt) 

comm compares (sorted) input files and by default outputs three columns: lines that are unique to a, lines that are unique to b, and lines that are present in both. By specifying -1, -2 and/or -3 you can suppress the corresponding output. Therefore comm -23 a b lists only the entries that are unique to a. I use the <(...) syntax to sort the files on the fly, if they are already sorted you don't need this.

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If you prefer the diff output style from git diff, you can use it with the --no-index flag to compare files not in a git repository:

git diff --no-index a.txt b.txt 

Using a couple of files with around 200k file name strings in each, I benchmarked (with the built-in timecommand) this approach vs some of the other answers here:

git diff --no-index a.txt b.txt # ~1.2s  comm -23 <(sort a.txt) <(sort b.txt) # ~0.2s  diff a.txt b.txt # ~2.6s  sdiff a.txt b.txt # ~2.7s  vimdiff a.txt b.txt # ~3.2s 

comm seems to be the fastest by far, while git diff --no-index appears to be the fastest approach for diff-style output.

Update 2018-03-25 You can actually omit the --no-index flag unless you are inside a git repository and want to compare untracked files within that repository. From the man pages:

This form is to compare the given two paths on the filesystem. You can omit the --no-index option when running the command in a working tree controlled by Git and at least one of the paths points outside the working tree, or when running the command outside a working tree controlled by Git.

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Try sdiff (man sdiff)

sdiff -s file1 file2 
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You can use diff tool in linux to compare two files. You can use --changed-group-format and --unchanged-group-format options to filter required data.

Following three options can use to select the relevant group for each option:

  • '%<' get lines from FILE1

  • '%>' get lines from FILE2

  • '' (empty string) for removing lines from both files.

E.g: diff --changed-group-format="%<" --unchanged-group-format="" file1.txt file2.txt

[root@vmoracle11 tmp]# cat file1.txt  test one test two test three test four test eight [root@vmoracle11 tmp]# cat file2.txt  test one test three test nine [root@vmoracle11 tmp]# diff --changed-group-format='%<' --unchanged-group-format='' file1.txt file2.txt  test two test four test eight 

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