GNU sed 的 debug 选项, 助你了解sed的执行流程

reyleon

曾以何时有个 sedsed 的 sed 调试工具, 用的好不欢喜
这两天无意间看了下 sed 的更新历史, 在GNU sed 4.6 版本中, 发现新增了一个 --debug 选项, 试用了一下, 一个字: 好
大家伙可以试试

1. NEWS
   
2. 
   
3. * Noteworthy changes in release 4.6 (2018-12-19) [stable]
   
4. 
   
5. ** Improvements
   
6. 
   
7.   sed now prints a clear error message when r/R/w/W (and s///w) commands
   
8.   are missing a filename. Previously, w/W commands would fail with confusing
   
9.   error message, while r/R would be a silent no-op.
   
10. 
    
11.   sed now uses fully-buffered output (instead of line-buffered) when
    
12.   writing to files. This should noticeably improve performance of "sed -i"
    
13.   and other write commands.
    
14.   Buffering can be disabled (as before) with "sed -u".
    
15. 
    
16.   sed in non-cygwin windows environments (e.g. mingw) now properly handles
    
17.   '\n' newlines in -b/--binary mode.
    
18. 
    
19. ** Bug fixes
    
20. 
    
21.   sed no longer accesses invalid memory (heap overflow) when given invalid
    
22.   backreferences in 's' command [bug#32082, present at least since sed-4.0.6].
    
23. 
    
24.   sed no longer adds extraneous NUL when given s/$//n command.
    
25.   [related to bug#32271, present since sed-4.0.7]
    
26. 
    
27.   sed no longer accesses invalid memory (heap overflow) with s/$//n regexes.
    
28.   [bug#32271, present since sed-4.3].
    
29. 
    
30. ** New Features
    
31. 
    
32. New option, --debug: print the input sed script in canonical form
    
33.   and annotate program execution.

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New option, --debug: print the input sed script in canonical form
  and annotate program execution.

1. $ seq 3 | sed --debug -e 's/./--&--/ ; 2d'
   
2.     SED PROGRAM:
   
3.       s/./--&--/
   
4.       2 d
   
5.     INPUT:   'STDIN' line 1
   
6.     PATTERN: 1
   
7.     COMMAND: s/./--&--/
   
8.     MATCHED REGEX REGISTERS
   
9.       regex[0] = 0-1 '1'
   
10.     PATTERN: --1--
    
11.     COMMAND: 2 d
    
12.     END-OF-CYCLE:
    
13.     --1--
    
14.     INPUT:   'STDIN' line 2
    
15.     PATTERN: 2
    
16.     COMMAND: s/./--&--/
    
17.     MATCHED REGEX REGISTERS
    
18.       regex[0] = 0-1 '2'
    
19.     PATTERN: --2--
    
20.     COMMAND: 2 d
    
21.     END-OF-CYCLE:
    
22.     INPUT:   'STDIN' line 3
    
23.     PATTERN: 3
    
24.     COMMAND: s/./--&--/
    
25.     MATCHED REGEX REGISTERS
    
26.       regex[0] = 0-1 '3'
    
27.     PATTERN: --3--
    
28.     COMMAND: 2 d
    
29.     END-OF-CYCLE:
    
30.     --3--

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yexingqi

确实不错哦。

Shell_HAT

Beautiful

waker

感谢分享