Bash two commands in curly braces?

Originally Posted by blumenwesen I want split the string from special position. 05.01.2022 date 1 to 05.01.2022 date | 05.01.2022 | 05.01. | 05. | 05

i need the length to cut.

Why?

#!/bin/sh
d='05.01.2022 date 1'
echo "$d"
echo "${d% *}"
echo "${d%% *}"
echo "${d%.*}".
echo "${d%%.*}".
echo "${d%%.*}"

Ok thank you, but is it unable thats work like this?

z="abcd"; a="d"
echo ${z:${z%%$a*}0:-1}
echo ${z:${z%%$a*}>2?0:-1}

Again. The part between colons must resolve to a number.

z="abcd"; a="d"
echo ${z:${z%%$a*}0:-1}

This is what happens here

1. ${z%%$a*} resolves to abc;
2. Bash takes abc as the name of a (numeric) variable;
3. If this variable is not defined (unset), it will expand to zero according to the shell arithmetic rules;
4. The result will be abc.

The result would be different in this case:

z=abcd;a=d;abc=1
echo ${z:${z%%$a*}:-1}

Can you tell why?

I already knew it is similar in the prinziep with many programming languages with the length limit, would of course fit better here.

z[@]
echo ${z:0:${z%%$a*}[@]-1} Fieldindex Error

This was just an example, I do not understand how the variable can be replaced at the beginning by the result and the curly brace can be defined in a curly bracket.

That's just an example, I don't understand how the variable at the beginning can be exchanged for the result and code in the curly brace can be defined inside a curly brace.

How can I integrate the first fragment of code into the second one without going through the variable specification?
If it's impossible, there is no length limit imposed by numbers can be defined?

y=${z%%$a*}
echo ${y:0:-1}
unplace to
${${z%%$a*}:0:-1}
or
${z%%$a*:0:-1}
or
${(${z%%$a*}):0:-1}

Originally Posted by blumenwesen ${${z%%$a*}:0:-1} or ${z%%$a*:0:-1} or ${(${z%%$a*}):0:-1}

None of these is possible in Bash.

What's your problem with having it in two statements?

Variable definition if not absolutely necessary often leads to it becoming confusing and it takes up memory, if several processes are to run a program as a starter and service, it can be a little more code and longer with old pcs.

Then, by combining code fragments in curly brackets, can also understand connections and syntax.

Originally Posted by blumenwesen Variable definition if not absolutely necessary often leads to it becoming confusing and it takes up memory, if several processes are to run a program as a starter and service, it can be a little more code and longer with old pcs. Then, by combining code fragments in curly brackets, can also understand connections and syntax.

No, that is just speculation. Writing unreadable code makes hard to understand/maintain it. Usually an additional variable has no any cost in speed and memory usage (especially when it holds only a few bytes) or at least it is extremely hard to measure and demonstrate. And bash is actually a slow language, this kind of "improvement" is completely futile.
Understandability depends on the structure of the code, the used function and variable names, not on the number of lines and curly brackets. Also you may add comments if you wish to explain...

I can read it better that way, and write in python as a starter without a paging file is code that has to be written very laboriously because the different quotation marks and special characters have to be taken into account several times, the python code is also more than double so long and taking longer to run because of the loading of the additional libraries that bash has direct access to.
Python libraries are constantly changing and therefore custom code would need to be updated pointlessly over and over again, especially if you still use 2.7.

The Posix standard defines ${ to be a variable modifier
That means it must be followed by the name of a variable, ${var

zsh (but not bash) has extended this to a value modifier, and the value may be any sub-expression.
So you can give zsh a try.