man sections

'man' (manual) is the most useful tool for sysadmin. We can use man to understand the command, configuration file format, etc. but man has different sections. they are:

    1      User Commands
    2      System Calls
    3      C Library Functions
    4      Devices and Special Files
    5      File Formats and Conventions
    6      Games et. Al.
    7      Miscellanea
    8      System Administration tools and Deamons

we can use command whatis to check how many sections a command will be in
as

root@ip-172-31-7-84:~# whatis time

time (7)             - overview of time and timers

time (1)             - run programs and summarize system resource usage

time (2)             - get time in seconds

then you can use:

man 7 time
man 1 time
man 2 time

to check different means of time in linux