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linuxglob

Execution of ls command in Linux

I don't understand the execution when ?? and * are used together.

The following files are in the current working directory:

abc.txt
abcd.txt
bcd.txt
amm.doc
ammc.txt

What is the return result after executing command ls a??.*

Solution 
  •  * Matches any string, including the null string (empty string)
 ? Matches any single character

    For exemples 

     Pattern a??.* matches abc.txt

    - (a,a)
    - (?,b)
    - (?,c)
    - (.,.)
    - (*,txt)

     Pattern a??.* don't matches abcd.txt

    - (a,a)
    - (?,b)
    - (?,c)
    - but . dont' matches with d

    Pattern a??.* don't matches bcd.txt because a don't matches with b.