Shell Programming and Scripting

ok, how about if you give a desired output based on the sample input files you provided.

gmrd.txt:

;;BAY GR;03;1344;432
;;BAY GR;04;4321;221
;;235649;03;2563;598
;;235649;03;2563;345
;;291802;00;2563;598
;;979217;00;2563;598
;;235649;03;2563;598
;;A0ABVB;00;2563;598
;;235649;03;2563;598

core.txt

;;BAY GR;00;123
;;NOASCOMGR;03;143
;;US36204YA782;00;156
;;A0ABVB;00;132


The desired output would look at field three of core.txt and compare that with field three of gmrd.txt and only print those lines where gmrd.txt has the same field three value as core.txt so the output would be:

output.txt:
;;BAY GR;03;1344;432
;;BAY GR;04;4321;221
;;A0ABVB;00;2563;598

Code:

awk '
  BEGIN {
  FS=OFS=";"
  }

  FNR==NR { arr[$3]= ($3 in arr) ? arr[$3] "\n" $0 : $0; next }
  $3 in arr { print arr[$3] }' gmrd.txt core.txt

this comes out with the following output:

./temp4.sh[8]: awk^JBEGIN {^JFS=OFS=";"^J}^J^JFNR==NR { arr[$3]= ($3 in arr) ? a
rr[$3] "\n" $0 : $0; next }^J$3 in arr { print arr[$3] }^Jgmrd.txt: not found

- could this be to do with the flavour of UNIX im using? (AIX)

I've only posted a relative AWK portion - the invokation sequence stayed the same.

I've reposted the entire "thing" now.

Code:

awk -F\; 'FNR==NR{arr[$3]=1;next};$3 in arr' core.txt gmrd.txt

;;BAY GR;03;1344;432
;;BAY GR;04;4321;221
;;A0ABVB;00;2563;598

Is anyone able to explain what vgersh99 has done above? I'm new to scripting and am finding it immensly difficult trying to figure out what the following statement does exactly:

awk '
BEGIN {
FS=OFS=";"
}

FNR==NR { arr[$3]= ($3 in arr) ? arr[$3] "\n" $0 : $0; next }
$3 in arr { print arr[$3] }' gmrd.txt core.txt


Particular points that I dont understand are:

Why do we set FNR==NR?
Also what is the question mark for after that statement arr[$3]= ($3 in arr) ?

What does the : do after the $0

Thanks in advance for any help