Linux Shell Scripting Cookbook - Second Edition

Field separators and iterators

The internal field separator (IFS) is an important concept in shell scripting. It is very useful while manipulating text data. We will now discuss delimiters that separate different data elements from single data stream. An internal field separator is a delimiter for a special purpose. An internal field separator is an environment variable that stores delimiting characters. It is the default delimiter string used by a running shell environment.

Consider the case where we need to iterate through words in a string or comma separated values (CSV). In the first case we will use IFS=" " and in the second, IFS=",". Let us see how to do it.

Getting ready

Consider the case of CSV data:

data="name,sex,rollno,location" To read ...