--help gives a short list. For the full details, read the manual page. The command man shows it:
text
learner@tidepool:~$ man head
HEAD(1) User Commands HEAD(1)
NAME
head - output the first part of files
SYNOPSIS
head [OPTION]... [FILE]...
DESCRIPTION
Options:
-c, --bytes=NUM print the first NUM bytes
-n, --lines=NUM print the first NUM lines (default 10)
...The sections
NAMEthe name and one line about what it does
SYNOPSISthe usage line, the same as in --help
DESCRIPTIONwhat the command does, and every flag
Manual pages on a real server are often long. They can also have sections such as EXAMPLES.
On a real server: the pager
On a real server, man shows the page one screen at a time. The program that does this is a pager. The prompt comes back only when you close it.
| Key | Does |
|---|---|
| Space | Show the next screen |
| Up and down arrows | Move one line |
/word, then Enter | Find word in the page |
q | Close the page and go back to the prompt |
In this course, man writes the full page at once, with no pager.
When there is no page
Not every command has a manual page:
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learner@tidepool:~$ man uptime
No manual entry for uptimeThe program can exist without a page. Try --help.