Shell script, the begin explanation in awk.

Explain:

begin{} The most common use of this particular pattern is variable assignment. Begin this pattern is when the file does not begin to read.

awk ' begin{fs= ': "; ofs="-"}{nf+=0}1", corresponding processing is 1:2:3---------> read the input delimiter into the output delimiter, but, awk has a problem, if you do not work on the field, It does not change the output delimiter, nf+=0, this assignment fart with no, NF value has not changed. However, this action is performed on the field. So the OFS will take effect. NF is present and NF is a field. Summary is a sentence: set OFS, must be a field operation.

Shell script, the begin explanation in awk.