Quine is a program which takes no input and prints its own code as its only output. For more detail see Quine (computing) - Wikipedia
Do you want to solve quine puzzle by yourself?
Do not open the following section until you are helpless and need a hint. 
self="""
print('self=""{}'.format('"'),end='')
for i in self:
print(i, end='')
print(3*'"')
print(self)"""
print('self=""{}'.format('"'),end='')
for i in self:
print(i, end='')
print(3*'"')
print(self)
I don’t know if I understand it fully.
Does this count as a quine ?:
#!/bin/bash
echo "$(<$0 )"
Congratulations! It does!
$ cat tkn.sh
#!/bin/bash
echo "$(<$0)"
$ ./tkn.sh
#!/bin/bash
echo "$(<$0)"
Update: It looks like it reads its code from file… That is it receives input. No, I’m afraid that does not qualify as quine.
Took me a while but I think I got it.
Does this qualify as a quine ? (no input files used)
echo $BASH_COMMAND
I think it is a marginal situation. May be you find interesting BashQuine - Greg's Wiki
Thanks for the link 
I tend to think that my solution is valid though
see: Bash Reference Manual
thom@monolith:~$ cat ./quine
echo $BASH_COMMAND
thom@monolith:~$ ./quine
echo $BASH_COMMAND
EDIT: I just took a peek at your link. Seems that they also came up with my solution. According to that site, it is considered valid. 
