The GNU ps auxf command combines several useful flags:

• a: Shows processes from all users
• u: Displays user-oriented format
• x: Includes processes without a terminal
• f: Shows process hierarchy as ASCII art tree

This combination is particularly valuable for visualizing parent-child process relationships in Linux systems.

BSD-derived systems (including macOS) implement ps differently from GNU systems. Key differences:

• BSD ps doesn't support the GNU-style combined flags
• BSD uses different flag conventions (often single dash instead of no dash)
• Tree display requires different approaches

The most direct BSD equivalent would be:

ps aux -O pid,ppid,pgid,command

For the closest equivalent to ps auxf on BSD/macOS, use:

ps ax -o pid,ppid,user,pcpu,pmem,vsz,rss,start,time,command -M

To show the process hierarchy as a tree:

ps ax -o pid,ppid,command

Or for a more visual tree representation:

ps ax -o pid,ppid,command | awk '{ printf "%"$2*2"s", ""; print }'

For those who frequently need GNU-style ps behavior on macOS:

# Install GNU ps via Homebrew
brew install procps

# Then use:
gps auxf

Another useful macOS-specific command for process hierarchy:

pstree -w

Example output from BSD-style ps showing parent/child relationships:

PID  PPID COMMAND
1    0    /sbin/launchd
123  1    /usr/sbin/syslogd
456  1    /usr/libexec/UserEventAgent
789  456  /usr/libexec/secinitd

To filter for a specific process tree:

ps -ef -O pid,ppid | grep [process_name]

Key columns in BSD ps output:

• PID: Process ID
• PPID: Parent Process ID
• %CPU: CPU usage percentage
• %MEM: Memory usage percentage
• COMMAND: Full command with arguments

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When working on BSD-derived systems like macOS (formerly OS X), Linux users often miss the familiar ps auxf command that displays processes in a hierarchical tree structure. The BSD implementation of ps differs significantly from its GNU counterpart in both syntax and available options.

The BSD ps doesn't support the GNU-style auxf flags combination. Instead, it uses:

ps ax -o pid,user,command

However, this lacks the process tree visualization that f provides in GNU systems.

For tree-style process listing on BSD/macOS, we have several options:

1. Using pstree (if available)

Install via Homebrew on macOS:

brew install pstree

Then run:

pstree -p

2. BSD-Compatible ps Command

This provides similar output to ps auxf:

ps -axjf

3. Custom Formatting

For more control over output:

ps -ax -o pid,ppid,user,command

Here's a Bash function to mimic ps auxf behavior:

function bsd_ps_auxf() {
    ps -ax -o pid,ppid,user,pcpu,pmem,vsz,rss,tt,stat,start,time,command 
    | awk 'NR==1; NR>1 {print $0 | "sort -k2 -n"}'
}

• BSD ps doesn't support the f forest flag
• Column headers differ between implementations
• BSD uses -o for custom output formatting
• Memory reporting metrics vary

For those regularly switching between Linux and BSD systems, consider creating aliases in your shell configuration:

alias psauxf='ps -axjf'  # For BSD/macOS
alias psauxf-linux='ps auxf'  # For GNU/Linux