when I use ctags to generate tags file ,it generate tags and TAGS.the two file have different inode,and not hardlink or softlink .when I rm one,the other file also removed.


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[test@test src]$ ls -l tags
ls: cannot access tags: No such file or directory
[test@test src]$ ls -l TAGS
ls: cannot access TAGS: No such file or directory
[test@test src]$ ctags *ls*
[test@test src]$ ls -l tags
-rwxrwxrwx. 1 root root 23048 Apr 29 01:35 tags
[test@test src]$ ls -l TAGS
-rwxrwxrwx. 1 root root 23048 Apr 29 01:35 TAGS
[test@test src]$
[test@test src]$ stat tags
File: ‘tags’
Size: 23048 Blocks: 48 IO Block: 1024 regular file
Device: 26h/38d Inode: 7505 Links: 1
Access: (0777/-rwxrwxrwx) Uid: ( 0/ root) Gid: ( 0/ root)
Context: system_ubject_r:vmblock_t:s0
Access: 2018-04-29 01:35:30.210935000 +0800
Modify: 2018-04-29 01:35:30.234936400 +0800
Change: 2018-04-29 01:35:30.234936400 +0800
Birth: -
[test@test src]$ stat TAGS
File: ‘TAGS’
Size: 23048 Blocks: 48 IO Block: 1024 regular file
Device: 26h/38d Inode: 1407374883789031 Links: 1
Access: (0777/-rwxrwxrwx) Uid: ( 0/ root) Gid: ( 0/ root)
Context: system_ubject_r:vmblock_t:s0
Access: 2018-04-29 01:35:30.210935000 +0800
Modify: 2018-04-29 01:35:30.234936400 +0800
Change: 2018-04-29 01:35:30.234936400 +0800
Birth: -
[test@test src]$ diff tags TAGS
[test@test src]$ rm TAGS
[test@test src]$ ls -l tags
ls: cannot access tags: No such file or directory
[test@test src]$ ls -l TAGS
ls: cannot access TAGS: No such file or directory
[test@test src]$
###########################################
I use CENTOS 7
[test@test src]$ uname -a
Linux test.localdomain 3.10.0-693.el7.x86_64 #1 SMP Tue Aug 22 21:09:27 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
[test@test src]$


[test@test src]$ ctags --help
Exuberant Ctags 5.8, Copyright (C) 1996-2009 Darren Hiebert
Compiled: Jun 9 2014, 21:59:46
Addresses: <dhiebert@users.sourceforge.net>, http://ctags.sourceforge.net
Optional compiled features: +wildcards, +regex

Usage: ctags [options] [file(s)]


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did you read through this yet?
http://ctags.sourceforge.net/ctags.html

but it doesn't explain why when I rm TAGS ,tags file also removed.

bad coding or it was designed that way? got a read the code to find out.

found the cause,I use VMWARE player to share WINDOWS folder,there is only one file,but it's not case-sensitive,so I can ls both TAGS and tags.

glad you found out.