Re: understanding the T command

[Pietro Paolini]

Hello,

The 'Ttb' commands will jump at the end of the script therefore no 
action is taken after the first match.

'in which case the next cycle is started' means that the next input line 
will be read from sdtin.


On 5/15/20 12:13 PM, Nora Platiel wrote:
> Hello,
> I'm confused about conditional branching, especially the T command. Consider 
> this script:
>
> s/x/X/; #1
> T     ; #2
> s/y/Y/; #3
> T     ; #4
> s/^/Z/; #5
>
> Input line "x" produces output line "X", why not "ZX"?
>
> This is what I would expect to happen for line "x":
> - replacement #1 is successful
> - conditional branch #2 is not taken
> - replacement #3 is not successful
> - conditional branch #4 is not taken
> - replacement #5 is successful
>
> Conditional branch #4 should not be taken because replacement #1 succeeded, and 
> no line is read nor conditional branch taken between #1 and #4.
> I hope someone here can clarify.
> Thanks.
>
>  From the docs:
> T label: (test) Branch to label only if there have been no successful 
> substitutions since the last input line was read or conditional branch was 
> taken. The label may be omitted, in which case the next cycle is started.