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PS command and process handling
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Simple get pid of a program

> pidof sshd
121923

User information of a process

USER         PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root      121923  0.0  0.0  26508  7428 ?        Ss   Jul21   0:00 /usr/sbin/ssh

Full Command line (no header, wide or no truncation)

> ps h -p 121923 -o args -ww
/usr/sbin/sshd -D

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Getting environment (initial environment only)

Most programs do not update their runtime environment.

That include shells like BASH that does not change their environment,
only internally saves what should be passed to new program exec() calls.

NOTE: The size of the environment area a process is fixed, and can
not be expanded by the program. Though thay can change the contents.
Most programs don't do this except say for security, or as an alternative
method or reporting status (Like changing their argv arguments - like sendmail)

> ps e -p 127887 -ww
   PID TTY      STAT   TIME COMMAND
127887 pts/4    Rl+  261:33 python -u run_model.py test zh_en zh_en_model --del_edges 2 -use_pretrained_embedding XDG_SESSION_ID=2322 HOSTNAME=cockatrice.emperor SHELL=/bin/bash TERM=screen HISTSIZE=1000 SSH_CLIENT=10.0.0.200 47708 22 CONDA_SHLVL=2 CONDA_PROMPT_MODIFIER=(KGM) ...


Better to get it from /proc
But this only works if you have permission, and you handle 'NUL' separators.

  # sed 's/\x0/\n/g' /proc/127887/environ
  #> tr \\0 \\n < /proc/127887/environ
  xargs -0n1 echo < /proc/$$/environ

  XDG_SESSION_ID=2322
  HOSTNAME=cockatrice.emperor
  SHELL=/bin/bash
  TERM=screen
  HISTSIZE=1000
  ...

Or extract a specific value

> grep -z ^PWD= /proc/127887/environ; echo
PWD=/home/bigdata/thomas/chung/Crosslingula-KG-Matching


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To get the CURRENT environment of a process you will need to use "gdb"

  gdb program pid

    # THEN Run the following script to dump the environment
    set variable $foo = (char **) environ
    set $i = 0
    while ($foo[$i] != 0)
    print $foo[$i++]
    end

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