Any nsswitch.conf file line beginning with a hash character (#) is interpreted as a comment line and is ignored by routines that search the file.
When a hash character (#) is included in the middle of the line, characters to the left of the hash mark (before the hash mark) are interpreted by routines that search the nsswitch.conf file; characters to the right of the hash mark (after the hash mark) are interpreted as comments and not acted upon.
Table 2-4 Switch File Comment Examples| Type of Line | Example | 
|---|---|
| Comment line (not interpreted). | # hosts: nisplus [NOTFOUND=return] files | 
| Fully interpreted line. | hosts: nisplus [NOTFOUND=return] file | 
| Partially interpreted line (the files element not interpreted) | hosts: nisplus [NOTFOUND=return] # files |