Linux下经常会用到ldd查看程序使用了哪些共享链接库，很方便的一个工具，在Mac OS X上没有这个命令，如果想在Mac OS X查看程序使用了哪些链接库可以用otool 来代替。
例：
$ otool -L /usr/bin/vim
/usr/bin/vim:
/usr/lib/libncurses.5.4.dylib (compatibility version 5.4.0, current version 5.4.0)
/usr/lib/libiconv.2.dylib (compatibility version 7.0.0, current version 7.0.0)
/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1213.0.0)
otool还有很多其它参数：
-f print the fat headers
-a print the archive header
-h print the mach header
-l print the load commands
-L print shared libraries used
-D print shared library id name
-t print the text section (disassemble with -v)
-p <routine name> start dissassemble from routine name
-s <segname> <sectname> print contents of section
-d print the data section
-o print the Objective-C segment
-r print the relocation entries
-S print the table of contents of a library
-T print the table of contents of a dynamic shared library
-M print the module table of a dynamic shared library
-R print the reference table of a dynamic shared library
-I print the indirect symbol table
-H print the two-level hints table
-G print the data in code table
-v print verbosely (symbolically) when possible
-V print disassembled operands symbolically
-c print argument strings of a core file
-X print no leading addresses or headers
-m don't use archive(member) syntax
-B force Thumb disassembly (ARM objects only)
-q use llvm's disassembler (the default)
-Q use otool(1)'s disassembler
-mcpu=arg use `arg' as the cpu for disassembly
-j print opcode bytes
-C print linker optimization hints
--version print the version of otool
详细使用请参看手册。
Linux中的strace可以查看程序运行时的系统调用，有时对于调试程序很有帮助，Mac OS X中可用dtruss (需要root)替代
例：
sudo dtruss df -h
其它参数：
-p PID # examine this PID
-n name # examine this process name
-t syscall # examine this syscall only
-a # print all details
-c # print syscall counts
-d # print relative times (us)
-e # print elapsed times (us)
-f # follow children
-l # force printing pid/lwpid
-o # print on cpu times
-s # print stack backtraces
-L # don't print pid/lwpid
-b bufsize # dynamic variable buf size
eg,
dtruss df -h # run and examine "df -h"
dtruss -p 1871 # examine PID 1871
dtruss -n tar # examine all processes called "tar"
dtruss -f test.sh # run test.sh and follow children
详细请参考手册。