왜 `ps e`는 `ps`보다 더 많은 프로세스를 표시합니까?

ps매뉴얼 페이지 에서 :

기본적으로 ps는 현재 사용자와 동일한 유효 사용자 ID(euid=EUID)를 갖고 호출자와 동일한 터미널에 연결된 모든 프로세스를 선택합니다.

내 Ubuntu 시스템에서는 ps플래그가 없는 출력이 예상한 대로입니다.

$ ps
  PID TTY          TIME CMD
 6444 pts/11   00:00:00 bash
14605 pts/11   00:00:00 ps

이제 psOUTPUT MODIFIERS에 대한 매뉴얼 페이지에서 다시 살펴보겠습니다.

e      Show the environment after the command.

하지만 시도하면 ps e더 많은 프로세스가 나열됩니다.

$ ps e
  PID TTY      STAT   TIME COMMAND
   85 pts/1    Ss+    0:00 -bash HOSTTYPE=x86_64 LANG=C.UTF-8 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:
  100 pts/2    Ss+    0:00 -bash HOSTTYPE=x86_64 LANG=C.UTF-8 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:
  115 pts/3    Ss+    0:00 -bash HOSTTYPE=x86_64 LANG=C.UTF-8 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:
  130 pts/4    Ss+    0:00 -bash HOSTTYPE=x86_64 LANG=C.UTF-8 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:
  146 pts/5    Ss+    0:00 -bash HOSTTYPE=x86_64 LANG=C.UTF-8 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:
  174 pts/6    Ss+    0:00 -bash HOSTTYPE=x86_64 LANG=C.UTF-8 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:
 2988 pts/9    Ss     0:01 -bash HOSTTYPE=x86_64 LANG=C.UTF-8 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:
 3477 pts/9    S+     0:00 vi stepniak.json SHELL=/bin/bash WSL_DISTRO_NAME=Ubuntu-20.04 WT_SESSION=55c420c4-12cf-4f4c-b957-b0b42e2777b8 JAVA_HOME=/home/myr
 4513 pts/0    Ss+    0:02 -bash HOSTTYPE=x86_64 LANG=C.UTF-8 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:
 4540 pts/7    Ss+    0:00 -bash HOSTTYPE=x86_64 LANG=C.UTF-8 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:
 5653 pts/10   Ss+    0:01 -bash HOSTTYPE=x86_64 LANG=C.UTF-8 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:
 6444 pts/11   Ss     0:00 -bash HOSTTYPE=x86_64 LANG=C.UTF-8 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:
 7942 pts/12   Ss     0:00 -bash HOSTTYPE=x86_64 LANG=C.UTF-8 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:
17962 pts/12   Sl     0:03 /home/myroot/jdk-11.0.2/bin/java -classpath /mnt/c/k8s-developer/maven-3.6.3/boot/plexus-classworlds-2.6.0.jar -Dclassworlds.conf
17997 pts/11   R+     0:00 ps e SHELL=/bin/bash WSL_DISTRO_NAME=Ubuntu-20.04 WT_SESSION=7e85f66b-c77a-42da-8782-c0912c196b46 JAVA_HOME=/home/myroot/jdk-11.0
24958 pts/12   Sl     1:05 java -jar myapp.jar SHELL=/bin/bash WSL_DISTRO_NAME=Ubuntu-20.04 WT_SESSION=d9a61855-27fe-4757-a7c9-a38f38fe7fc7 JAVA
25185 pts/12   S+     0:03 tail -f nohup.out SHELL=/bin/bash WSL_DISTRO_NAME=Ubuntu-20.04 WT_SESSION=d9a61855-27fe-4757-a7c9-a38f38fe7fc7 JAVA_HOME=/home/my

내 이해에 따르면 e는 OUTPUT 수정자이며 프로세스를 선택하는 데 사용되는 기준을 변경해서는 안 됩니다(일반적으로 등으로 수행됨 -e) a.

그렇다면 왜 ps e더 많은 프로세스가 나열되어 있습니까 ps?

노트: ps -f또는 ps -F예상대로 작동합니다 -

$ ps -F
UID        PID  PPID  C    SZ   RSS PSR STIME TTY          TIME CMD
myroot    6444  6443  0  4333 12404   2 00:25 pts/11   00:00:00 -bash
myroot   19976  6444  0  2655  3340   7 23:05 pts/11   00:00:00 ps -F

내 운영 체제 정보:

$ cat /etc/*rel*
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=20.04
DISTRIB_CODENAME=focal
DISTRIB_DESCRIPTION="Ubuntu 20.04.3 LTS"
NAME="Ubuntu"
VERSION="20.04.3 LTS (Focal Fossa)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 20.04.3 LTS"
VERSION_ID="20.04"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=focal
UBUNTU_CODENAME=focal