Software Engineer

This can be done by iterative swapping using two pointers. The first pointer points to the beginning of the string, whereas the second pointer points to the end. Both pointers keep swapping their elements and go towards each other. Essentially, the algorithm simulates the rotation of a string with respect to its midpoint.
Time Complexity : O(n)

Approach : Using hashing
Algorithm: 
1: Construct character count array from the input string.
2: Print all the indexes from the constructed array which have values greater than 1.

The cut command in UNIX is a command for cutting out the sections from each line of files and writing the result to standard output. It can be used to cut parts of a line by byte position, character and field. Basically the cut command slices a line and extracts the text. It is necessary to specify option with command otherwise it gives error. If more than one file name is provided then data from each file is not precedes by its file name.

Syntax: cut OPTION... [FILE]...

The find command in UNIX is a command line utility for walking a file hierarchy. It can be used to find files and directories and perform subsequent operations on them. It supports searching by file, folder, name, creation date, modification date, owner and permissions. By using the ‘-exec’ other UNIX commands can be executed on files or folders found.

Syntax : $ find [where to start searching from]
[expression determines what to find] [-options] [what to find]