$ docker run --rm -e POSTGRES_PASSWORD=mysecretpassword -d postgres:13
a9fd95ccfeaeaa94c0a0a39deac52e74f59841607258c6827eabd2b33972f633
$ docker exec -it a9fd95ccfeaeaa94c0a0a39deac52e74f59841607258c6827eabd2b33972f633 bash
root@661543604ec8:/# apt-get update && apt-get install -y procps
<snip>
root@661543604ec8:/# psql -U postgres -c 'SELECT pg_sleep(60)' &
[1] 463
root@661543604ec8:/# ps auxww
USER         PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
postgres       1  0.0  0.1 213072 27168 ?        Ss   14:45   0:00 postgres
postgres      62  0.0  0.0 213072  4232 ?        Ss   14:45   0:00 postgres: checkpointer 
postgres      63  0.0  0.0 213072  5896 ?        Ss   14:45   0:00 postgres: background writer 
postgres      64  0.0  0.0 213072 10084 ?        Ss   14:45   0:00 postgres: walwriter 
postgres      65  0.0  0.0 213628  8532 ?        Ss   14:45   0:00 postgres: autovacuum launcher 
postgres      66  0.0  0.0  67428  4792 ?        Ss   14:45   0:00 postgres: stats collector 
postgres      67  0.0  0.0 213504  6896 ?        Ss   14:45   0:00 postgres: logical replication launcher 
root          68  0.0  0.0   7092  3748 pts/0    Ss   14:46   0:00 bash
root         463  1.5  0.0  20480  8296 pts/0    S    14:47   0:00 /usr/lib/postgresql/13/bin/psql -U postgres -c SELECT pg_sleep(60)
postgres     464  0.0  0.0 214028 11688 ?        Ss   14:47   0:00 postgres: postgres postgres [local] SELECT
root         465  0.0  0.0   9692  3308 pts/0    R+   14:47   0:00 ps auxww