手冊頁中 (1) 的含義是什麼？

與man bc，我有一條以 開頭的行bc(1)。

bc(1)                                                                    bc(1)

NAME
      bc - An arbitrary precision calculator language

一些 Unix 書還描述了帶有 (1) 的 Unix 命令，就像這個 SO 問題一樣 - https://stackoverflow.com/questions/8402181/how-do-i-get-bc1-to-print-the-leading-零。這是什麼意思？

是手冊的章節號。

來自man man：

The table below shows the section numbers of the manual followed by the types of pages they contain.

1   Executable programs or shell commands
2   System calls (functions provided by the kernel)
3   Library calls (functions within program libraries)
4   Special files (usually found in /dev)
5   File formats and conventions eg /etc/passwd
6   Games
7   Miscellaneous (including macro packages and conventions), e.g. man(7), groff(7)
8   System administration commands (usually only for root)
9   Kernel routines [Non standard]

引用自：https://unix.stackexchange.com/questions/249428