topunix/pst

:deciduous_tree: A reproduction of pstree

Hi there, I'm Mike 👋

• 🌎 I’m a web developer from the United States
• ❤ Contributing to Open Source.
• 🐍 I specialize in Python and Django, but my programming experience extends across multiple languages and tools
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• ⚡ Fun fact: Before using Git, I worked with various version control systems including Mercurial, SVN, CVS, and Perforce

Blog posts 📰

• AWS Lambda and Celery for Asynchronous Tasks in Django
• Effortless Django & React: Introducing Reactivated
• Building a Fort: Django Security Best Practices
• Cracking the Code: Mastering Algorithmic Problem-Solving for Interviews

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pst's Issues

not giving correct process tree

The tree given by pst.py does not correspond to process tree

ps -e -o pid,ppid,args
  PID  PPID COMMAND
    1     0 /init
    6     1 /init
    7     6 /init
    8     7 -bash
  473     8 sleep 3000
  474     8 ps -e -o pid,ppid,args

$ pstree -spa
init,1
  ├─init,6
  │   └─init,7
  │       └─bash,8
  │           ├─pstree,475 -spa
  │           └─sleep,473 3000
  └─{init},5

$ ./pst.py -w
  PID  COMMAND
    1  /init
    6   \_ /init
    7   \_ /init
    8           \_ -bash
  476               \_ python ./pst.py -w
  477                   \_ ps -e l
  473                       \_ sleep 3000    <= father is 8 not 477

not working as expected when ppid greater than pid

When child pid less than its parent, the ps command will display child before parent (see 375 1051 bash line in example)

it seems bad supposition in format_process_trees :

# Parent always comes before child

# ps -ef -o pid,ppid,args
  PID  PPID COMMAND
    1     0 /init
    6     1 /init
    7     6 /init
    8     7 -bash
  375  1051 bash
  383   375 bash
  396   383 ps -e -o pid,ppid,args
  636     1 /init
  637   636 /init
  638   637 -bash
 1011     8 bash
 1019  1011 bash
 1027  1019 bash
 1035  1027 bash
 1051  1035 bash

# ./pst.py -w
  PID  COMMAND
    1  /init
    6   \_ /init
    7   \_ /init
    8   |       \_ -bash
 1011   |           \_ bash
 1019   |               \_ bash
 1027   |                   \_ bash
 1035   |                       \_ bash
 1051   |                           \_ bash
  636   \_ /init
  637   \_ /init
  638           \_ -bash
  375  bash                                 <====== is child of 1051 !
  383   \_ bash
  392   \_ python ./pst.py -w
  393           \_ ps -e l

# pstree -ap
init,1
  ├─init,6
  │   └─init,7
  │       └─bash,8
  │           └─bash,1011
  │               └─bash,1019
  │                   └─bash,1027
  │                       └─bash,1035
  │                           └─bash,1051
  │                               └─bash,375
  │                                   └─bash,383
  │                                       └─pstree,407 -ap
  ├─init,636
  │   └─init,637
  │       └─bash,638
  └─{init},5