Re: History modifier :p ignored prior to another history reference

[Piotr Grzybowski]

Hey,

 confirmed, this is what happens by construction.
 this one is going to be tricky, expansion happens on the shell line, way 
before it comes to execution. I do not see reparsing again at execute_command 
even if we had means, which we dont, to store the information from history 
expansion to know what to execute and what not. Re-tokenizing by rules of 
history expansion anywhere outside histexpand seems out of place as much as 
implementing shell lexer (again) in histexpand. Maybe splitting in 
history_expand and returning tokens with options, that are later put together 
for execution? Either way seems a bit large. 
 Currently the design indicates: :p applies to the whole line.
 Maybe I am mistaken, correctly me if I am wrong.

cheers,
pg


On 3 May 2016, at 18:15, Dean Stanton wrote:

> Configuration Information [Automatically generated, do not change]:
> Machine: x86_64
> OS: linux-gnu
> Compiler: gcc
> Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='x86_64' 
> -DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='x86_64-redhat-linux-gnu' 
> -DCONF_VENDOR='redhat' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash' 
> -DSHELL -DHAVE_CONFIG_H   -I.  -I. -I./include 
> -I./lib  -D_GNU_SOURCE -DRECYCLES_PIDS  -O2 -g -pipe -Wall 
> -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector 
> --param=ssp-buffer-size=4 -m64 -mtune=generic
> uname output: Linux dstanton-vm.tintri.com 2.6.32.26-175.fc12.x86_64 #1 SMP 
> Wed Dec 1 21:39:34 UTC 2010 x86_64 x86_64 x86_64 GNU/Linux
> Machine Type: x86_64-redhat-linux-gnu
> 
> Bash Version: 4.0
> Patch Level: 38
> Release Status: release
> 
> Description:
> History modifier :p is not honored when it appears prior to another history 
> reference on the same command line.
> 
>         I tried to find a website with known bash bugs (to search to see if 
> this issue was already discussed), but didn't find such a site.
> 
> Repeat-By:
> $ echo one two three four
>         one two three four
>         $ echo !:2:p ; echo !$          # :p was ignored!
>         echo two ; echo four
>         two
>         four
> 
> $ echo one two three four
>         one two three four
>         $ echo !:p !!       # :p was ignored!
> echo one two three four echo one two three four
> one two three four echo one two three four
> 
> 
>         I expected the entire command line to be only printed and not 
> executed. The manpage says
>        p      Print the new command but do not execute it.
>         Instead, the :p was ignored and the entire command line was (printed 
> and then) executed.
> 
>         $ echo one two three four
>         one two three four
>         $ echo !:2 ; echo !$:p          # :p was heeded.
>         echo two ; echo four
> $ echo one two three four
> $ echo !:1:p !$
> # :p was ignored
> echo one four
> one four
> 
>