sed: Programming Commands

1 
1 3.6 Commands for 'sed' gurus
1 ============================
1 
1 In most cases, use of these commands indicates that you are probably
1 better off programming in something like 'awk' or Perl.  But
1 occasionally one is committed to sticking with 'sed', and these commands
1 can enable one to write quite convoluted scripts.
1 
1 ': LABEL'
1      [No addresses allowed.]
1 
1      Specify the location of LABEL for branch commands.  In all other
1      respects, a no-op.
1 
1 'b LABEL'
1      Unconditionally branch to LABEL.  The LABEL may be omitted, in
1      which case the next cycle is started.
1 
1 't LABEL'
1      Branch to LABEL only if there has been a successful 's'ubstitution
1      since the last input line was read or conditional branch was taken.
1      The LABEL may be omitted, in which case the next cycle is started.
1