find difference between two text files with one item per line [duplicate]

Answer 1

If you want to use loops You can try like this: (diff and cmp are much more efficient. )

while read line
do
    flag = 0
    while read line2
    do
       if ( "$line" = "$line2" )
        then
            flag = 1
        fi
     done < file1 
     if ( flag -eq 0 )
     then
         echo $line > file3
     fi
done < file2

Note: The program is only to provide a basic insight into what can be done if u dont want to use system calls such as diff n comm..

Answer 2

file1 
m1
m2
m3

file2 
m2
m4
m5

>awk 'NR == FNR {file1[$0]++; next} !($0 in file1)' file1 file2
m4
m5

>awk 'NR == FNR {file1[$0]++; next} ($0 in file1)' file1 file2
m2

> What's awk command to get 'm1 and m3' ??  as in file1 and not in file2? 
m1
m3

Answer 3

if you are expecting them in a certain order, you can just use diff

diff file1 file2 | grep ">"

Answer 4

I successfully used

diff "${file1}" "${file2}" | grep "<" | sed 's/^<//g' > "${diff_file}"

Outputting the difference to a file.

Answer 5

join -v 2 <(sort file1) <(sort file2)

Answer 6

You can use the comm command to compare two sorted files

comm -13 <(sort file1) <(sort file2)