Help & Apropos

LLDB是新一代高性能调试器，是Xcode的默认调试器，并且支持调试C/C++程序。
LLDB命令繁多，下面开始接少一下常用的命令。

• 打开Mac终端输入lldb 进入lldb调试模式。

(lldb)help
Debugger commands:
  apropos           -- List debugger commands related to a word or subject.
  breakpoint        -- Commands for operating on breakpoints (see 'help b' for
                       shorthand.)
  bugreport         -- Commands for creating domain-specific bug reports.
  command           -- Commands for managing custom LLDB commands.
  disassemble       -- Disassemble specified instructions in the current
                       target.  Defaults to the current function for the
                       current thread and stack frame.
  expression        -- Evaluate an expression on the current thread.  Displays
                       any returned value with LLDB's default formatting.
  frame             -- Commands for selecting and examing the current thread's
                       stack frames.
  gdb-remote        -- Connect to a process via remote GDB server.  If no host
                       is specifed, localhost is assumed.
  gui               -- Switch into the curses based GUI mode.
  help              -- Show a list of all debugger commands, or give details
                       about a specific command.
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会出现全部的lldb命令，许多命令还有好多子命令。
以breakpoint命令为例：会列出详细的子命令及其解释等

(lldb) help breakpoint
 Commands for operating on breakpoints (see 'help b' for shorthand.)

Syntax: breakpoint <subcommand> [<command-options>]

The following subcommands are supported:

      clear   -- Delete or disable breakpoints matching the specified source
                 file and line.
      command -- Commands for adding, removing and listing LLDB commands
                 executed when a breakpoint is hit.
      delete  -- Delete the specified breakpoint(s).  If no breakpoints are
                 specified, delete them all.
      disable -- Disable the specified breakpoint(s) without deleting them.  If
                 none are specified, disable all breakpoints.
      enable  -- Enable the specified disabled breakpoint(s). If no breakpoints
                 are specified, enable all of them.
      list    -- List some or all breakpoints at configurable levels of detail.
      modify  -- Modify the options on a breakpoint or set of breakpoints in
                 the executable.  If no breakpoint is specified, acts on the
                 last created breakpoint.  With the exception of -e, -d and -i,
                 passing an empty argument clears the modification.
      name    -- Commands to manage name tags for breakpoints
      read    -- Read and set the breakpoints previously saved to a file with
                 "breakpoint write".  
      set     -- Sets a breakpoint or set of breakpoints in the executable.
      write   -- Write the breakpoints listed to a file that can be read in
                 with "breakpoint read".  If given no arguments, writes all
                 breakpoints.

For more help on any particular subcommand, type 'help <command> <subcommand>'.
(lldb) 

• apropos 命令作用在于搜索 例如

//搜索有关“swift”的命令
(lldb)apropos swift
//相关命令
The following commands may relate to 'swift':
  swift    -- A set of commands for operating on the Swift Language Runtime.
  demangle -- Demangle a Swift mangled name
  refcount -- Inspect the reference count data for a Swift object

//相关设置
The following settings variables may relate to 'swift': 


  target.swift-framework-search-paths -- List of directories to be searched
                                         when locating frameworks for Swift.
  target.swift-module-search-paths -- List of directories to be searched when
                                      locating modules for Swift.
  target.use-all-compiler-flags -- Try to use compiler flags for all modules
                                   when setting up the Swift expression parser,
                                   not just the main executable.
  target.experimental.swift-create-module-contexts-in-parallel -- Create the per-module Swift AST contexts in parallel.