Shell Programming and Scripting

Using unix shell script, how to compare two files and print lines with mismatch? Below are the requirements:
1. The number of lines on the two files is not the same.
2. The difference/mismatch can be found on the second or third column.
3. The comparison is not between line 1 of file 1 and line 1 of file 2. Rather, the comparison is on line 1 of file 1 and the line on file 2 that has the same first word on the line 1 of file 1.


To demonstrate:
FILE 1:
abc 123 678
def 456 901
ghi 789 234
jkl 012 567
mno 345 890
FILE 2:
def 456 901
abc 124 678
mno 345 890
ghi 789 244
OUTPUT FILE:
"from file 1"
abc 123 678
ghi 789 234
"from file 2"
abc 124 678
ghi 789 244

i hope someone can help me with this. Thanks!

Try this..

Code:

awk '{ if (FNR==NR) {arr[$1]=$0;next}
if (($1 in arr) && ($0!=arr[$1])) { f1[$1]=arr[$1]; f2[$1]=$0; next} } 
END { print "from file 1";  for (i in f1) {print f1[i]}; print "from file 2"; for (i in f2) {print f2[i]}  } ' file1 file2 > file3

Assumption: First word is unique in a given file. please let me know if you need to handle duplicates also so that I can try for that.

hi king! the code you gave me doesn't work..
it doesn't print the lines with difference though i am sure that there are lines that have mismatch on the two files.

Thanks!

What have you tried?

i tried diff command But i learned that in diff command, it compares line by line.
while in cat file1 file2 | sort | uniq -u > file 3, it yileds:

ABC 123
ABC 321
DEF 412
DEF 124

and when i used it on my script, it yields a odd number of lines.

Is this what you want...

Code:

sort file1 > file1_tmp
sort file2 > file2_tmp
sdiff file1_tmp file2_tmp | grep '|'

output:

Code:

abc 123 678                                                     |  abc 124 678
ghi 789 234                                                     |  ghi 789 244

output should be:

"FROM FILE 1"
ABC 123
ABC 321


"FROM FILE2"
DEF 412
DEF 124