python - Compare 2 files and remove any lines in file2 when they match values found in file1

Question

I have two files. i am trying to remove any lines in file2 when they match values found in file1. One file has a listing like so:

File1

ZNI008
ZNI009
ZNI010
ZNI011
ZNI012

... over 19463 lines

The second file includes lines that match the items listed in first: File2

copy /Y \serverfoldernameversion20050001_ZNI008_162635.xml \serverfoldernameversionfolder
copy /Y \serverfoldernameversion20050001_ZNI010_162635.xml \serverfoldernameversionfolder
copy /Y \serverfoldernameversion20050001_ZNI012_162635.xml \serverfoldernameversionfolder
copy /Y \serverfoldernameversion20050001_ZNI009_162635.xml \serverfoldernameversionfolder

... continues listing until line 51360

What I've tried so far:

grep -v -i -f file1.txt file2.txt > f3.txt

does not produce any output to f3.txt or remove any lines. I verified by running

wc -l file2.txt

and the result is

51360 file2.txt

I believe the reason is that there are no exact matches. When I run the following it shows nothing

comm -1 -2 file1.txt file2.txt

Running

( tr '' '
' < file1.txt; tr '' '
' < file2.txt ) | sort | uniq -c | egrep -v '^ +1'

shows only one match, even though I can clearly see there is more than one match.

Alternatively putting all the data into one file and running the following:

grep -Ev "$(cat file1.txt)" 1>LinesRemoved.log

says argument has too many lines to process.

I need to remove lines matching the items in file1 from file2.

i am also trying this in python: `

    #!/usr/bin/python
s = set()

# load each line of file1 into memory as elements of a set, 's'
f1 = open("file1.txt", "r")
for line in f1:
    s.add(line.strip())
f1.close()

# open file2 and split each line on "_" separator,
# second field contains the value ZNIxxx
f2 = open("file2.txt", "r")
for line in f2:
    if line[0:4] == "copy":
        fields = line.split("_")
        # check if the field exists in the set 's'
        if fields[1] not in s:
            match = line
        else:
            match = 0
    else:
        if match:
            print match, line,

`

it is not working well.. as im getting 'Traceback (most recent call last): File "./test.py", line 14, in ? if fields[1] not in s: IndexError: list index out of range'

Answer 1

What about:

grep -F -v -f file1 file2 > file3