`awk' Statements versus Lines
=============================

   Most often, each line in an `awk' program is a separate statement or
separate rule, like this:

     awk '/12/  { print $0 }
          /21/  { print $0 }' BBS-list inventory-shipped

   But sometimes statements can be more than one line, and lines can
contain several statements.  You can split a statement into multiple
lines by inserting a newline after any of the following:

     ,    {    ?    :    ||    &&    do    else

A newline at any other point is considered the end of the statement.
(Splitting lines after `?' and `:' is a minor `gawk' extension.  The
`?' and `:' referred to here is the three operand conditional
expression described in See Conditional Expressions: Conditional Exp.)

   If you would like to split a single statement into two lines at a
point where a newline would terminate it, you can "continue" it by
ending the first line with a backslash character, `\'.  This is allowed
absolutely anywhere in the statement, even in the middle of a string or
regular expression.  For example:

     awk '/This program is too long, so continue it\
      on the next line/ { print $1 }'

We have generally not used backslash continuation in the sample
programs in this manual.  Since in `gawk' there is no limit on the
length of a line, it is never strictly necessary; it just makes
programs prettier.  We have preferred to make them even more pretty by
keeping the statements short.  Backslash continuation is most useful
when your `awk' program is in a separate source file, instead of typed
in on the command line.  You should also note that many `awk'
implementations are more picky about where you may use backslash
continuation.  For maximal portability of your `awk' programs, it is
best not to split your lines in the middle of a regular expression or a
string.

   *Warning: backslash continuation does not work as described above
with the C shell.*  Continuation with backslash works for `awk'
programs in files, and also for one-shot programs *provided* you are
using a POSIX-compliant shell, such as the Bourne shell or the
Bourne-again shell.  But the C shell used on Berkeley Unix behaves
differently!  There, you must use two backslashes in a row, followed by
a newline.

   When `awk' statements within one rule are short, you might want to
put more than one of them on a line.  You do this by separating the
statements with a semicolon, `;'.  This also applies to the rules
themselves.  Thus, the previous program could have been written:

     /12/ { print $0 } ; /21/ { print $0 }

*Note:* the requirement that rules on the same line must be separated
with a semicolon is a recent change in the `awk' language; it was done
for consistency with the treatment of statements within an action.