sed - awk | merge line on the basis of field matching

Question

I need help with following:

Input file:

abc message=sent session:111,x,y,z
pqr message=receive session:111,4,5,7
abc message=sent session:123,x,y,z
pqr message=receive session:123,4,5,7
abc message=sent session:342,x,y,z
abc message=sent session:589,x,y,z
pqr message=receive session:589,4,5,7

Output file:

abc message=sent session:111,x,y,z, pqr message=receive session:111,4,5,7
abc message=sent session:123,x,y,z, pqr message=receive session:123,4,5,7
abc message=sent session:342,x,y,z, NOMATCH
abc message=sent session:589,x,y,z, pqr message=receive session:589,4,5,7

Notes:

If you see in source file, for every "sent" message there is "receive"
only for session=342 there is no receive
session is unknow, can't be hardcoded
So merge only those sent and receive where we have matching session number

Answer 1

Here's one way using awk. Run like:

awk -f script.awk file

Contents of script.awk:

{
    x = $0

    gsub(/[^:]*:|,.*/,"")

    a[$0] = (a[$0] ? a[$0] "," FS : "") x
    b[$0]++
}

END {
    for (i in a) {
        print (b[i] == 2 ? a[i] : a[i] "," FS "NOMATCH") | "sort"
    }
}

Results:

abc message=sent session:111,x,y,z, pqr message=receive session:111,4,5,7
abc message=sent session:123,x,y,z, pqr message=receive session:123,4,5,7
abc message=sent session:342,x,y,z, NOMATCH
abc message=sent session:589,x,y,z, pqr message=receive session:589,4,5,7

Alternatively, here's the one-liner:

awk '{ x = $0; gsub(/[^:]*:|,.*/,""); a[$0] = (a[$0] ? a[$0] "," FS : "") x; b[$0]++ } END { for (i in a) print (b[i] == 2 ? a[i] : a[i] "," FS "NOMATCH") | "sort" }' file

Note that you can drop the pipe to sort if you don't care about sorted output. HTH.