Ever wondering how you can man other manual pages within less? There are some programs can do that with built-in feature like pinfo‘s hypertext feature. What if with less?

The only way I know is using ! shell-command to invoke a new process of less, from less(1):

! shell-command
Invokes a shell to run the shell-command given. A percent sign (%) in the command is replaced by the name of the current file. A pound sign (#) is replaced by the name of the previously examined file. “!!” repeats the last shell command. “!” with no shell command simply invokes a shell. On Unix systems, the shell is taken from the environment variable SHELL, or defaults to “sh”. On MS-DOS and OS/2 systems, the shell is the normal command processor.

For example, say you already does man man, now in less if you type in:

!man less

The less(1) is brought up to you, if you quit, you will go back to man(1). The new manpage is produced and loaded in different processes, not the ones you read man(1) on

If you less a normal file, and you want to open another, use :e, stands for examine not edit as in Vim term. You can use :p and :n to switch betweens the opened files. It’s more or less like :bp and :bn in Vim.