file1.txt
/123/456/789/active/161208/avg_speed_and_avg_velocity_161208.html
/123/456/789/active/205510/210.html
/123/456/789/active/143416/CS_MM_GGB_15.htm
/123/456/789/active/174498/CS_AP_GGB_14.html
/123/456/789/active/174221/open_pipe_1741.html
/123/456/789/active/143449/images/ime007.gif
/123/456/789/active/143449/images/ime006.png
/123/456/789/active/143449/images/imag02.gif
/123/456/789/active/143449/images/Thms.db
/123/456/789/active/143449/images/ima01.png

file2.txt
/123/456/789/active/143416/
/123/456/789/active/174498/
/123/456/789/active/174221/
/123/456/789/active/143449/

output file1.txt(must be)

/123/456/789/active/161208/avg_speed_and_avg_velocity_161208.html
/123/456/789/active/205510/205510.html

My intention is file1.txt-file2.txt=file1.txt means the file1.txt itself should be the output file(if posible), don't want to be created a 3rd file for output. The repeated lines also should be deleted from the file1.txt. It is clear that if the string is matches a line the particular line should be deleted even if there are number of matching lines also.

looks like a homework.
the solution depends on the size of the files.
if file2 is relatively small you can simply run grep -v line by line.
otherwise you would need to create a script: sort both files and make a loop.

2 members found this post helpful.

Hi,

have you considered using grep iwth the -v and -f options? I think this will do what you want, but it will require you to use a temporary file.

Eg.
Evo2.

I neeed to delete 4000 lines file from a 2.2 lack lines file, hoping with out generating a 3rd file. The above mention is just a sample for better understanding.

so you can try the solution of evo2, actually it will not create a third file (just a temporary file was created, but also removed at the end).
You can try:
also, if you would like to. This is not a really safe solution

Ofcourse not a safe Solution @pan64
its good if you can do the redirect output to a third file.

Eliminate the cat to tighten this code a bit...
Daniel B. Martin