結論

.bashrcと.bashrc_profileファイルに以下を追加すればOK.

.bashrc

if [ -f /.dockerenv ]; then
    PS1='[${debian_chroot:+($debion_chroot)}\u@\h:\w]\$'
fi

.bash_profile

source ~/.bashrc

補足

dockerコンテナを立ち上げると自動的にコンテナ内に.dockerenvというファイルが作られるので、そのファイルがあるかどうか判別して、あるときだけプロンプトに[　]を追加.

dockerコンテナ内

[user@hostname:/]$cd /
[user@hostname:/]$ls -la
total 96
drwxr-xr-x   1 root root 4096 Mar  4 11:08 .
drwxr-xr-x   1 root root 4096 Mar  4 11:08 ..
-rwxr-xr-x   1 root root    0 Mar  4 11:07 .dockerenv
drwxr-xr-x   1 root root 4096 Feb  3 16:39 bazel
drwxr-xr-x   2 root root 4096 Oct 18 21:03 bin
drwxr-xr-x   2 root root 4096 Apr 24  2018 boot
drwxr-xr-x   5 root root  460 Mar  7 07:05 dev
drwxr-xr-x   1 root root 4096 Mar  7 07:05 etc
drwxr-xr-x   1 root root 4096 Mar  4 11:08 home
-rw-r--r--   1 root root  782 Sep 13 18:12 intelpython3-2019.0-047_amd64.deb
drwxr-xr-x   1 root root 4096 Nov 13 00:13 lib
drwxr-xr-x   2 root root 4096 Oct 18 21:02 lib64
drwxr-xr-x   2 root root 4096 Oct 18 21:02 media
drwxr-xr-x   2 root root 4096 Oct 18 21:02 mnt
drwxr-xr-x   1 root root 4096 Feb  3 18:04 opt
dr-xr-xr-x 411 root root    0 Mar  7 07:05 proc
drwx------   1 root root 4096 Feb  3 18:03 root
drwxr-xr-x   1 root root 4096 Mar  4 11:08 run
-rwxr-xr-x   1 root root  733 Jan  9 08:00 run_jupyter.sh
drwxr-xr-x   1 root root 4096 Jan  9 08:00 sbin
drwxr-xr-x   2 root root 4096 Oct 18 21:02 srv
dr-xr-xr-x  13 root root    0 Feb  2 13:11 sys
drwxrwxrwt   1 root root 4096 Mar  4 11:08 tmp
drwxr-xr-x   1 root root 4096 Oct 18 21:02 usr
drwxr-xr-x   1 root root 4096 Feb  3 16:40 var
drwxr-xr-x   1 root root 4096 Feb  3 18:04 workspace