I have two files with genes

File one (with 40000 genes)

    Gene 1
    Gene 2
    Gene 3
    Gene b
    Gene f
    Gene c
    Gene r
    Gene z


File two (with 39000 genes)

    Gene 1
    Gene 3
    Gene 2
    Gene b


I would like to know if there is a command line (with awk or bash) to extract that lines that exist in the one file and not in the two file
> I would like to know if there is a command line (with awk or bash) to extract that lines that exist in the one file and not in the two file

use comm : http://man7.org/linux/man-pages/man1/comm.1.html

    comm -3 <(sort file1.txt)  <(sort file2.txt ) 