(1 point) Write a script nl_4digits.sh which uses a while and read commands to reading a standard input and inserting a number at the beginning of line together with a double colon.
# Example input:
Hi Jack,
how are you?
# Example output:
0001: Hi Jack,
0002: how are you?
(1 point) Write a script palindrome.sh [argument] which takes as argument either file name or -.
If filename is provided it process lines from file. If - is provided it process lines from stdin.
For each line it decides whether it is a palindrome. If it is not palindrome it skips the line otherwise it prints the palindrome to standard output.
(1 point) Write a script evener.sh which keeps only even lines in the input file
hints: seq, seq -n, sed 'command1;command2;command3' file