0

I have two files, file1.txt contains strings separated by commas:

1.1.1.1,string1,comment1
7.7.7.7,string3,comment3
2.2.2.2,string2,comment2
88.88.88.88,string4,comment4
999.999,999,999,string5,comment5

The second file, file2.txt, contains strings that can appear in the first column of file1.txt. I need to remove the whole row in file1.txt if its first column's string appears in file2.txt. Please note that I do not want to change th original file, but I want to put the output in a new file.

  • 1
    If you don't need to restrict the match to the first column of file1.txt specifically, then probably something like grep -vFf file2.txt file1.txt > newfile should do – steeldriver Oct 7 '18 at 23:01
1

Why not simply

grep -vffile2 file1
-f FILE: Obtain patterns from FILE, one per line.
-v:      Invert the sense of matching, to select non-matching lines.
0

You can try something like

#!/bin/bash 
cat file2.txt | while IFS=, read line; do

sed -i "/$(grep $line file1.txt)/d" file1.txt

done

Be aware that sed -i will make direct changes to file1.txt, but you can change the command to sed -i.ibk in order to save a backup copy of the original file.

For example

$cat file2.txt 
1.1.1.1
7.7.7.7

$cat file1.txt 
1.1.1.1,string1,comment1
7.7.7.7,string3,comment3
2.2.2.2,string2,comment2
88.88.88.88,string4,comment4
999.999,999,999,string5,comment5

output 
2.2.2.2,string2,comment2
88.88.88.88,string4,comment4
999.999,999,999,string5,comment5
  • In order to make sure the result is correct, sed can be used on its own without the i so that the changes are only sent to stdout. – Nasir Riley Oct 7 '18 at 23:39

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.