awk BEGIN END and string matching problem

Shell Programming and Scripting
1

Hi,
Contents of BBS-list file:

foo
foo
foo

awk '
BEGIN { print "Analysis of \"foo\"" }
/foo/ { ++n }
END   { print "\"foo\" appears", n, "times." }' BBS-list

Output:

Analysis of "foo"
"foo" appears 3 times.

awk '
BEGIN { print "Analysis of \"foo\"" }
/foo/ { ++n }
++n
END   { print "\"foo\" appears", n, "times." }' BBS-list

Output:

Analysis of "foo"
foo 
foo
foo
"foo" appears 6 times.

Why does it print the contents of BBS-list file if i add ++n?

2

'++n' standing 'alone' is a condition with a missing 'action' - no corresponding '{...}'.
As '++n' (condition) is incremented and is NOT '0'. The default 'action' for a non-zero 'condition' is to print an entire current record/line.

3

Try this as example and see the output...
1 means true, in ur example, n++ is always positive so it prints for u all records...

awk '
BEGIN { print "Analysis of \"foo\"" }
/foo/ { ++n }1' BBS-list
4

Thank you very much.