gawk: If Statement
7.4.1 The 'if'-'else' Statement
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The 'if'-'else' statement is 'awk''s decision-making statement. It
looks like this:
'if (CONDITION) THEN-BODY' ['else ELSE-BODY']
The CONDITION is an expression that controls what the rest of the
statement does. If the CONDITION is true, THEN-BODY is executed;
otherwise, ELSE-BODY is executed. The 'else' part of the statement is
optional. The condition is considered false if its value is zero or the
null string; otherwise, the condition is true. Refer to the following:
if (x % 2 == 0)
print "x is even"
else
print "x is odd"
In this example, if the expression 'x % 2 == 0' is true (i.e., if the
value of 'x' is evenly divisible by two), then the first 'print'
statement is executed; otherwise, the second 'print' statement is
executed. If the 'else' keyword appears on the same line as THEN-BODY
and THEN-BODY is not a compound statement (i.e., not surrounded by
braces), then a semicolon must separate THEN-BODY from the 'else'. To
illustrate this, the previous example can be rewritten as:
if (x % 2 == 0) print "x is even"; else
print "x is odd"
If the ';' is left out, 'awk' can't interpret the statement and it
produces a syntax error. Don't actually write programs this way,
because a human reader might fail to see the 'else' if it is not the
first thing on its line.
Info Catalog
gawk: Statements
gawk: While Statement