Functions

All sed commands require a function to tell them what to do; the command itself is a combination of an address and a function. Functions are named by a single character. The following types of function are available:

• Whole-line oriented functions that add, delete, and change whole text lines.

• Substitute functions that search and substitute regular expressions within a line.

• Input-output functions that read and write lines and/or files.

• Multiple input-line functions that match patterns that extend across line boundaries.

• Hold and get functions that save and retrieve input text for later use.

• Flow-of-control functions that control the order of application of functions.

• Miscellaneous functions.