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This question already has an answer here:

I have an account with secondary group membership in a group that owns a directory. The directory is chmod 760, which should allow writing to the directory, but not listing it. However, this is not allowed. Can somebody explain why?

Rationale: mostly academic; trying to understand permissions in detail. I recognize that I could make the permissions 770 and allow this; I'm not an idiot (at least I don't think so). I just want to understand what write permissions actually mean for a directory, if not file creation.

Code example:

powerdave@dhirsch-centos:/tmp >groups
powerdave wheel share
powerdave@dhirsch-centos:/tmp >ls -alh
total 124K
drwxrwxrwt.  5 root      root      4.0K Feb 23 15:08 ./
dr-xr-xr-x. 23 root      root      4.0K Feb 23 14:57 ../
drwxrw----.  2 guest     share     4.0K Feb 23 14:52 test/
powerdave@dhirsch-centos:/tmp >touch test/file
touch: cannot touch `test/file': Permission denied

marked as duplicate by Gilles linux Feb 24 '15 at 21:43

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • So, after reading that "duplicate", the question remains: is there any meaning to +w on a directory if +x is required for all the writing operations? – Dave Hirsch Feb 25 '15 at 0:26
2
  • r allows listing — just the names.
  • w deleting and adding.
  • t prevents deleting — if you don't own it.
  • x allows navigation — stating a file or directory: reading meta data, reading meta-data is needed to be able to access, add or delete a file within the directory.

If you can not navigate, then you can not delete, add, or anything else.

  • So is there any useful use of a directory with no x? Maybe to taunt: look at all these files, that you can no access. – ctrl-alt-delor Feb 23 '15 at 23:29
  • The problem I'm seeing is this part: "w deleting and adding". Adding doesn't seem to actually be true! I can't add a new file - see original post. – Dave Hirsch Feb 24 '15 at 3:41
  • Edited answer to be clearer. – ctrl-alt-delor Feb 24 '15 at 19:46

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