How to remove matching lines from one text file using another

text processing

I am trying to remove matching lines from one text file using another. For example, fired.txt contains:

Jason
Candice
Brent
Tom

And I want to remove matching lines from workers.txt, which currently looks like this:

Andrew
Tommy
Peter
Jason
Brent
Sasha
Tom
Candice

So, in the end, it would remove the entire line if it matches exactly, so it would look like this:

Andrew
Tommy
Peter
Sasha

I am using macOS Sierra, btw.

Best Answer

Short grep approach:

grep -xvf fired.txt workers.txt

The output:

Andrew
Tommy
Peter
Sasha

grep options:

x - Select only those matches that exactly match the whole line
v - Invert the sense of matching, to select non-matching lines
f (--file=file) - Obtain patterns from file, one per line

Related Solutions

Text Processing with sed/awk – Replace All Text After a Certain Line

Using sed:

sed -n -e '1,/^### REPLACE EVERYTHING AFTER THIS LINE ###$/{ p; d; }' \
       -e 'r replacement_file.txt' \
       -e 'q' original_file.txt

The three sed blocks do this:

The first block prints all lines from line 1 to the line with the special contents. I print these lines explicitly with p and then invoke d to force a new cycle to start ("print; next" in awk).
After the initial lines have been outputted by the first block, the second block outputs the contents of the extra file.
The editing script is then terminated.

Ordinarily, q in the third block would output the current line before quitting (this would be the line in the example data reading text_that_will), but since sed is invoked with -n, this default outputting of a line at the end of a cycle is inhibited.

The result of the above command, given your data, is

common_text
### REPLACE EVERYTHING AFTER THIS LINE ###
testing123
this_is_the_replacement_text

To update the original file, you could use sed -i ..., or redirect the output to a new file that you then replace the original with:

sed ... original_file.txt >original_file.txt.new &&
mv original_file.txt.new original_file.txt

Best Answer

Related Solutions

Text Processing with sed/awk – Replace All Text After a Certain Line

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