Linux in a Nutshell, 6th Edition

Name

getline

Synopsis

getline
getline [var] [< file]
command | getline [var]
command |& getline [var] {G}

Read next line of input.

The second form reads input from file, and the third form reads the output of command. All forms read one record at a time, and each time the statement is executed, it gets the next record of input. The record is assigned to $0 and is parsed into fields, setting NF, NR and FNR. If var is specified, the result is assigned to var and $0 and NF are not changed. Thus, if the result is assigned to a variable, the current record does not change. getline is actually a function, and it returns 1 if it reads a record successfully, 0 if end-of-file is encountered, and −1 if for some reason it is otherwise unsuccessful.

The fourth form reads the output from coprocess command. See the section Coprocesses and Sockets in Coprocesses and Sockets for more information.