linux - cut matched and put in another location -

How can I cut numbers that are in the square brackets and put them at the beginning of the text? For example:

  some_text123_ [12345] after _some_text: 12345_some_text123 _ [] _ ​​some_text    < P> 
 
 I tried to use  perl .  
 This Pearl should work a liner.    $ echoing some Atekote 123_ [123] _some_text | Perl -ne 'print "$ 1_", "$` "," $' \ '\ \ "if / \ [(\ d +?) \] /; $ <->  
 $ `-   
 Just to explain the special variable from perl regex engine:  
 $ 1 - How do I protect it on mail Want to  
 $ `-  
 $ '- after everything after match