help in awk arrays!

Shell Programming and Scripting
1

Hi, buddies

I am new to shell scripting and trying to solve a problem. I read about arrays in awk that they are quite powerful and are associative in nature.

Awk Gurus Please help!

I have a file:

Id1 pp1 0t4 pp8 xy2
Id43 009y black
Id6 red xy2
Id12 new pp1 black

I have another file :

Id pp1 black new pp8

The output should be like: (Ids of file1 and their matching elements from file2)

Id1 pp1 pp8
Id43 black
Id6 
Id12 new

looking forward for your suggestions.
Cheers!

2

Thanks a lot! ctsgnb for such an elaborate explaination. Its very informative for me.
But, I was wondering that the last line is printed as it is because it should be

Id12 new

otherwise.

3

Why would that be? All 3 elements (new pp1 black) are in file2, no?

1 Like
4

O! Ya! sorry, I even miss wrote in my thread and then just compared it with the same.
Thanks! again.

---------- Post updated at 08:43 PM ---------- Previous update was at 08:34 PM ----------

I have one question. How does it know that the code below is now for second file?

 
{for(k=0;++k<=NF;)

and can we deal with more than two files with awk?

5

1) This is because of the instruction "next", next skip any further code and reprocess next line from the beginning of awk commands

2) yes, awk can deal with more than 2 files, consider the following code :

$ cat f3
line1
line2
line3
line4
line5

$ nawk '{print NR,FNR,FILENAME,$0}' f3 f1 f2 f3 f2
1 1 f3 line1
2 2 f3 line2
3 3 f3 line3
4 4 f3 line4
5 5 f3 line5
6 1 f1 Id1 pp1 0t4 pp8 xy2
7 2 f1 Id43 009y black
8 3 f1 Id6 red xy2
9 4 f1 Id12 new pp1 black
10 1 f2 Id pp1 black new pp8
11 1 f3 line1
12 2 f3 line2
13 3 f3 line3
14 4 f3 line4
15 5 f3 line5
16 1 f2 Id pp1 black new pp8