AbortOn will quit on the anticipated error gracefully without stack trace.

Abs returns the absolute value of x.

Basename returns the file name without extension.

IsExist checks if the given file exist.

Verbose will print info to stderr according to the verbose level setting.

Warning will print the given string as a Warning.

WarnOn will print the error message as a Warning, if applicable, and retur true if so.

The OptsT type defines all the configurable options from cli.