Related to the issues with the ? event designator, the %word designator
substitutes the *first* word matched by the ? event designator or nothing
if the match begins with a space. These details are not documented.
[root@localhost ~]# echo a b c d >/dev/nul
[root@localhost ~]# echo !?b c?
echo echo a b c d >/dev/nul
[root@localhost ~]# echo "!%"
echo "b"
b
[root@localhost ~]# echo a1 >/dev/nul
[root@localhost ~]# echo !? a?
echo echo a1 >/dev/nul
[root@localhost ~]# echo "!%"
echo ""
Jim
On Sun, Nov 3, 2019 at 9:18 AM Jim Monte wrote:
> Two more documentation issues I have found are below.
>
> It appears that an empty substring event designator uses the string of the
> previous substring event designator if none is provided and does not find
> the event if there is no previous string.
>
> [root@localhost ~]# ls
> dos hello.c
> [root@localhost ~]# cat hello.c > /dev/nul
> [root@localhost ~]# echo !?s?
> echo ls
> ls
> [root@localhost ~]# echo !??
> echo echo ls
> echo ls
> [root@localhost ~]# ls -al > /dev/nul
> [root@localhost ~]# echo !??
> echo ls -al > /dev/nul
> [root@localhost ~]# echo s
> s
> [root@localhost ~]# echo !??
> echo echo s
> echo s
> [root@localhost ~]# echo !?l?
> echo echo ls -al > /dev/nul
> [root@localhost ~]# echo !??
> echo echo echo ls -al > /dev/nul
>
> [root@localhost ~]# bash
> [root@localhost ~]# echo !??
> bash: !??: event not found
>
> This action is not documented.
>
>
>
>
>
> An empty "old" string in a substitute word modifier uses the previous
> "old" if none is given, but uses an empty string if new is empty. If there
> was no previous "old" string, an error is reported.
>
> [root@localhost ~]# echo f g i
> f g i
> [root@localhost ~]# echo !:s/g/k/
> echo echo f k i
> echo f k i
> [root@localhost ~]# echo af ag ai
> af ag ai
> [root@localhost ~]# echo !:s///
> echo echo af a ai
> echo af a ai
> [root@localhost ~]# echo bf bg bi
> bf bg bi
> [root@localhost ~]# echo !:s//1/
> echo echo bf b1 bi
> echo bf b1 bi
> [root@localhost ~]# echo gf gg gi
> gf gg gi
> [root@localhost ~]# echo !:gs//2/
> echo echo 2f 22 2i
> echo 2f 22 2i
>
> [root@localhost ~]# bash
> [root@localhost ~]# echo a b c
> a b c
> [root@localhost ~]# echo !:s//1/
> bash: :s//1/: no previous substitution
>
> Again, this behavior is not documented.
>
> On Thu, Oct 10, 2019 at 10:35 PM Jim Monte wrote:
>
>> Hi,
>>
>> This bug report has been my first one for Bash. I have not found how to
>> check the status of the bug. Would you please provide this information?
>>
>> Below are a couple more issues I found.
>>
>> There is an inconsistency with the documentation and behavior of the ^
>> word designator. According to documentation, it refers to the first
>> argument but does not require a ':' before it if it starts the word
>> designator. However, it does not act like the numerical word designator 1
>> at the end of a range.
>>
>> [root@localhost ~]# echo a b c
>> a b c
>> [root@localhost ~]# echo !!:1-1
>> echo a
>> a
>> [root@localhost ~]# echo a b c
>> a b c
>> [root@localhost ~]# echo !!:^-^
>> echo a b^
>> a b^
>>
>> Also it is not explicitly documented that :- is equivalent to :0-
>>
>> [root@localhost ~]# echo a b c d
>> a b c d
>> [root@localhost ~]# echo !!:-
>> echo echo a b c
>> echo a b c
>> [root@localhost ~]# echo a b c d
>> a b c d
>> [root@localhost ~]# echo !!:0-
>> echo echo a b c
>> echo a b c
>>
>>
>> Jim Monte
>>
>> On Thu, Oct 3, 2019 at 6:19 PM Jim Monte wrote:
>>
>>> Hi All,
>>>
>>> Below are some issues I found with history substitution. I am
>>> duplicating its behavior in a somewhat different use, and found issues with
>>> the documentation and bugs as described.
>>>
>>> Jim Monte
>>>
>>>
>>>
>>>
>>> From: jim
>>> To: bug-bash@gnu.org
>>> Subject: Issues with history substitution and its documentation
>>>
>>> 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='l$
>>> uname output: Linux T5500-Ubuntu 4.18.0-22-generic #23~18.04.1-Ubuntu
>>> SMP Thu J$
>>> Machine Type: x86_64-pc-linux-gnu
>>>
>>> Bash Version: 4.4
>>> Patch Level: 19
>>> Release Status: release
>>>
>>> Description:
>>>
>>> =
>>> Documentation of quick substitution is incorrect (or does not match
>>> behavior).
>>>
>>> I believe this issue is an error with the documentation of history
>>> "Quick Substitution" that has existed since the first snapshot available
>>> at
>>> web.archive.org in 2007 at
>>>
>>>
>>> https://web.archive.org/web/20071223174140/http://www.gnu.org/software/bash/manual/html_node/Event-Designators.html
>>>
>>> At the least it is true that bash does not behave as the documentation
>>> states,
>>> but it does act in a way that is more reasonable (to me) than what is
>>> written.
>>>
>>> The documentation states that ^string1^string2^ is equivalent to
>>> !
