Linux Shell Scripting Cookbook - Third Edition

Field separators and iterators

The internal field separator (IFS) is an important concept in shell scripting. It is useful for manipulating text data.

An IFS is a delimiter for a special purpose. It 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=",".