Re: How to use ']' in the upper bound of a range character set

[Norihiro Tanaka]

Hi,

   We can't use and/or escape `]' between `[' and `]' in  grep and
egrep. Given cases is interpreted respectively as follows.

  - grep -E "[1-\]]" file_input

      [1-\]  ]  CAT

      where [1-\] is range cset.
 
 - grep -E "[1-\\]]" file_input

      [1-\\]    ]    CAT 

      where [1-\\] is cset. it's able to expand as following ...
 
      \([1-\]\|\\\)

  - grep -E "[1-]]" file_input

      [1-]    ]    CAT

      where [1-] is range cset which is endless.