在bash脚本中使用-s命令

Question

I have a trivial error that I cant seem to get around. Im trying to return the various section numbers of lets say "man" since it resides in all the sections. I am using the -s command but am having problems. Every time I use it I keep getting "what manual page do you want". Any help?

Answer 1

In the case of getting the section number of a command, you want something like man -k "page_name" | awk -F'-' "/^page_name \\(/ {print $1}" man -k "page_name" | awk -F'-' "/^page_name \\(/ {print $1}" , replacing any occurrence of page_name with whatever command you're needing.

This won't work for all systems necessarily as the format for the "man" output is "implementation-defined". In other words, the format on FreeBSD, OS X, various flavours of Linux, etc. may not be the same. For example, mine is:

page_name (1)               - description

If you want the section number only, I'm sure there is something you can do such as saving the result of that line in a shell variable and use parameter expansion to remove the parentheses around the section number:

man -k "page_name" | awk -F'-' "/^page_name \(/ {print $1}" | while IFS= read sect ; do
    sect="${sect##*[(]}"
    sect="${sect%[)]*}"
    printf '%s\n' "$sect"
done

To get the number of sections a command appears in, add | wc -l | wc -l at the end on the same line as the done keyword. For the mount command, I have 3:

2
2freebsd
8

Answer 2

The correct syntax requires an argument. Typically you're looking for either

man -s 1 man

to read the documentation for the man(1) command, or

man -s 7 man

to read about the man(7) macro package.

If you want a list of standard sections, the former contains that. You may have additional sections installed locally, though. A directory listing of /usr/local/share/man might reveal additional sections, for example.

(Incidentally, -s is not a "command" in this context, it's an option.)

Answer 3

You've misinterpreted the nature of -s . From man man :

-S list, -s list, --sections=list

List is a colon- or comma-separated list of `order specific' manual sections to search. This option overrides the $MANSECT environment variable. (The -s spelling is for compatibility with System V.)

So when man sees man -s man it thinks you want to look for a page in section "man" (which most likely doesn't exist, since it is not a normal section), but you didn't say what page, so it asks:

What manual page do you want?

BTW, wrt "man is just the test case cuz i believe its in all the sections" -- nope, it is probably only in one, and AFAIK there isn't any word with a page in all sections. More than 2 or 3 would be very unusual.

The various standard sections are described in man man too.