Built-in functions

length([String])

Returns the number of characters of the given String

If a number is given instead a String, the result will be the length of the String representing the given number. I.e. If we execute length(12345) the result will be the same as length("12345"), that is 5
If no value is given, the result will be the length of the actual row being processed, that is length($0)
It can be used inside a pattern or inside code-blocks.

Here are a few examples demonstrating how length()works

$ cat file
AAAAA
BBBB
CCCC
DDDD
EEEE

Inside a pattern

Filter all lines with a length bigger than 4 characters

$ awk ' length($0) > 4 ' file
AAAAA

Inside a code block

Will print the size of the current line

$ awk '{ print length($0) }' file
5
4
4
4
4

With no data given

Will print the size of the current line

$ awk '{ print length }' file
5
4
4
4
4

Will print the size of the current line

$ awk '{ print length() }' file
5
4
4
4
4

Number given instead of String

Will print the size of the String representing the number

$ awk '{ print length(12345) }' file
5
5
5
5
5

Fixed String given

Will print the size of the String

$ awk '{ print length("12345") }' file
5
5
5
5
5