Revision 4f900d2b-03db-4308-bab5-a6b734c95e8f - Code Golf Stack Exchange

# [Dash]*, <s>87</s> 86 bytes
<sub>*Actually this is aimed at Busybox 1.31.1 `ash`, `sed`, `seq` and `printf`, but TIO didn't have that environment. NB available `seq` options are pretty minimal.</sub>

<!-- language-all: lang-sh -->

 for p in `seq 9 -1 2;seq 9`;do seq -s"`printf "%${p}s_"`" 10;done|sed s/10/0/\;s/._//g

[Try it online!][TIO-kta07k7h]

[Dash]: https://wiki.debian.org/Shell
[TIO-kta07k7h]: https://tio.run/##Hco7DoAgEAXAq7wQLXHBznAVEzABPw0ga6eeHT/dFOMnXmudU0HGFuE47BggNXrz0xmf8EmycLls8Zgh2ubMN1vhBLR6QwwXBw8mrUjRaJg6S7TU@gA "Dash – Try It Online"

### Explanation

```
for p in `seq 9 -1 2;seq 9`
```
Produce 9-2, 1-9, used to create separator in next `seq`

```
;do seq -s"`printf "%${p}s_"`" 10
```
Print 1-10, separated with `p` × spaces, with marker `_` appended; results in 1 too many spaces (but `seq` won't accept an empty separator), the marker `_` helps us to remove the spare spaces below.

```
;done|sed s/10/0/\;s/._//g
```
Remove the 1 from trailing 10, remove the marker `_` and the extra space before it, to get the proper spacing.

*EDIT: removed a silly space (thanks Kevin Cruijssen)*