next Statement ¶The next statement forces awk to immediately stop processing
the current record and go on to the next record. This means that no
further rules are executed for the current record, and the rest of the
current rule’s action isn’t executed.
Contrast this with the effect of the getline function
(see Explicit Input with getline). That also causes
awk to read the next record immediately, but it does not alter the
flow of control in any way (i.e., the rest of the current action executes
with a new input record).
At the highest level, awk program execution is a loop that reads
an input record and then tests each rule’s pattern against it. If you
think of this loop as a for statement whose body contains the
rules, then the next statement is analogous to a continue
statement. It skips to the end of the body of this implicit loop and
executes the increment (which reads another record).
For example, suppose an awk program works only on records
with four fields, and it shouldn’t fail when given bad input. To avoid
complicating the rest of the program, write a “weed out” rule near
the beginning, in the following manner:
NF != 4 {
printf("%s:%d: skipped: NF != 4\n", FILENAME, FNR) > "/dev/stderr"
next
}
Because of the next statement,
the program’s subsequent rules won’t see the bad record. The error
message is redirected to the standard error output stream, as error
messages should be.
For more detail, see
Special File names in gawk.
If the next statement causes the end of the input to be reached,
then the code in any END rules is executed.
See The BEGIN and END Special Patterns.
The next statement is not allowed inside BEGINFILE and
ENDFILE rules. See The BEGINFILE and ENDFILE Special Patterns.
According to the POSIX standard, the behavior is undefined if the
next statement is used in a BEGIN or END rule.
gawk treats it as a syntax error. Although POSIX does not disallow it,
most other awk implementations don’t allow the next
statement inside function bodies (see User-Defined Functions). Just as with any
other next statement, a next statement inside a function
body reads the next record and starts processing it with the first rule
in the program.