Mastering Linux Shell Scripting

Built-in functions

In the previous example, we defined a function called green. This leads into taking about some built-in functions that come with awk.

AWK comes with many built-in functions such as mathematical functions:

• sin(x)
• cos(x)
• sqrt(x)
• exp(x)
• log(x)
• rand()

You can use them like this:

$ awk 'BEGIN{x=sqrt(5); print x}' 

Also, there are built-in functions that can be used in string manipulation:

$ awk 'BEGIN{x = "welcome"; print toupper(x)}'