(gawk.info.gz) Two Rules

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 1.4 An Example with Two Rules
 =============================
 
 The `awk' utility reads the input files one line at a time.  For each
 line, `awk' tries the patterns of each of the rules.  If several
 patterns match, then several actions are run in the order in which they
 appear in the `awk' program.  If no patterns match, then no actions are
 run.
 
    After processing all the rules that match the line (and perhaps
 there are none), `awk' reads the next line.  (However,  Next
 Statement, and also  Nextfile Statement).  This continues
 until the program reaches the end of the file.  For example, the
 following `awk' program contains two rules:
 
      /12/  { print $0 }
      /21/  { print $0 }
 
 The first rule has the string `12' as the pattern and `print $0' as the
 action.  The second rule has the string `21' as the pattern and also
 has `print $0' as the action.  Each rule's action is enclosed in its
 own pair of braces.
 
    This program prints every line that contains the string `12' _or_
 the string `21'.  If a line contains both strings, it is printed twice,
 once by each rule.
 
    This is what happens if we run this program on our two sample data
 files, `BBS-list' and `inventory-shipped':
 
      $ awk '/12/ { print $0 }
      >      /21/ { print $0 }' BBS-list inventory-shipped
      -| aardvark     555-5553     1200/300          B
      -| alpo-net     555-3412     2400/1200/300     A
      -| barfly       555-7685     1200/300          A
      -| bites        555-1675     2400/1200/300     A
      -| core         555-2912     1200/300          C
      -| fooey        555-1234     2400/1200/300     B
      -| foot         555-6699     1200/300          B
      -| macfoo       555-6480     1200/300          A
      -| sdace        555-3430     2400/1200/300     A
      -| sabafoo      555-2127     1200/300          C
      -| sabafoo      555-2127     1200/300          C
      -| Jan  21  36  64 620
      -| Apr  21  70  74 514
 
 Note how the line beginning with `sabafoo' in `BBS-list' was printed
 twice, once for each rule.
 

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