Copy Or Move File And Append Date Using Bash

bash version 4.2.46(2)-release

[ggs@db-fs-1 ~]$ echo "$SHELL"
/bin/bash
[ggs@db-fs-1 ~]$

[ggs@db-fs-1 ~]$ echo $BASH_VERSION
4.2.46(2)-release
[ggs@db-fs-1 ~]$

Demo 1:

[ggs@db-fs-1 ~]$ touch foo.log
[ggs@db-fs-1 ~]$ file=foo.log
[ggs@db-fs-1 ~]$
[ggs@db-fs-1 ~]$ ls -l $file*; cp -fv ${file%%.*}.{${file#*.},${file#*.}."$(date +%Y%m%d)"}; ls -l $file*
-rw-r--r-- 1 ggs oinstall 0 Apr 29 05:49 foo.log
‘foo.log’ -> ‘foo.log.20200429’
-rw-r--r-- 1 ggs oinstall 0 Apr 29 05:49 foo.log
-rw-r--r-- 1 ggs oinstall 0 Apr 29 05:50 foo.log.20200429
[ggs@db-fs-1 ~]$

Demo 2:

[ggs@db-fs-1 ~]$ touch archive.tar.gz
[ggs@db-fs-1 ~]$ file=archive.tar.gz
[ggs@db-fs-1 ~]$
[ggs@db-fs-1 ~]$ ls -l $file*; cp -fv ${file%%.*}.{${file#*.},${file#*.}."$(date +%Y%m%d)"}; ls -l $file*
-rw-r--r-- 1 ggs oinstall 0 Apr 29 05:48 archive.tar.gz
‘archive.tar.gz’ -> ‘archive.tar.gz.20200429’
-rw-r--r-- 1 ggs oinstall 0 Apr 29 05:48 archive.tar.gz
-rw-r--r-- 1 ggs oinstall 0 Apr 29 05:49 archive.tar.gz.20200429
[ggs@db-fs-1 ~]$

Demo 3: Rotate ggserr.log (only required because logrotate is not configured)

ggs@db-fs-1 ggs]$ file=ggserr.log
[ggs@db-fs-1 ggs]$ ls -l $file*; cp -fv ${file%%.*}.{${file#*.},${file#*.}."$(date +%Y%m%d)"}; ls -l $file*
-rw-r----- 1 ggs oinstall 534 Apr 29 06:04 ggserr.log
‘ggserr.log’ -> ‘ggserr.log.20200429’
-rw-r----- 1 ggs oinstall 534 Apr 29 06:04 ggserr.log
-rw-r----- 1 ggs oinstall 534 Apr 29 06:05 ggserr.log.20200429

[ggs@db-fs-1 ggs]$ cat /dev/null > ggserr.log
[ggs@db-fs-1 ggs]$ ls -l $file*
-rw-r----- 1 ggs oinstall   0 Apr 29 06:05 ggserr.log
-rw-r----- 1 ggs oinstall 534 Apr 29 06:05 ggserr.log.20200429
[ggs@db-fs-1 ggs]$

Demo 4:

[ggs@db-fs-1 ~]$ file=archive.tar.gz
[ggs@db-fs-1 ~]$ ls -l $file*; mv -fv ${file%%.*}.{${file#*.},${file#*.}."$(date +%Y%m%d)"}; ls -l $file*
-rw-r--r-- 1 ggs oinstall 0 Apr 29 05:48 archive.tar.gz
-rw-r--r-- 1 ggs oinstall 0 Apr 29 05:49 archive.tar.gz.20200429
‘archive.tar.gz’ -> ‘archive.tar.gz.20200429’
-rw-r--r-- 1 ggs oinstall 0 Apr 29 05:48 archive.tar.gz.20200429
[ggs@db-fs-1 ~]$

Why is this even important?

Consistent and mindless effort but need to remember syntax.