Node:Getline, Previous:Multiple Line, Up:Reading Files
getlineSo far we have been getting our input data from awk's main
input stream--either the standard input (usually your terminal, sometimes
the output from another program) or from the
files specified on the command line. The awk language has a
special built-in command called getline that
can be used to read input under your explicit control.
The getline command is used in several different ways and should
not be used by beginners.
The examples that follow the explanation of the getline command
include material that has not been covered yet. Therefore, come back
and study the getline command after you have reviewed the
rest of this Web page and have a good knowledge of how awk works.
The getline command returns one if it finds a record and zero if
it encounters the end of the file. If there is some error in getting
a record, such as a file that cannot be opened, then getline
returns -1. In this case, gawk sets the variable
ERRNO to a string describing the error that occurred.
In the following examples, command stands for a string value that represents a shell command.
getline with no arguments.
getline into a variable.
getline from a file.
getline into a variable from a
file.
getline from a pipe.
getline into a variable from a
pipe.
getline from a coprocess.
getline into a variable from a
coprocess.
getline.
getline Variants.