System Info

System Info

ps, env, date, hostname, whoami, which, balias, time, and sleep commands for process listing, environment inspection, and shell utilities.

---

ps

Report a snapshot of the current processes. Returns structured PsEntry objects with typed properties for process ID, CPU, memory, and more.

Syntax

ps [OPTIONS]

Flags

Flag	Description
aux	BSD-style: show all processes with full columns
-e / -A	Show all processes
-f	Full-format listing (current user’s processes, no TTY restriction)
-u USER	Filter by username
-p PID	Filter by process ID
--sort=KEY	Sort by key (prefix with - for descending)
-o COLS	Custom column output (comma-separated)

Sort keys: pid, ppid, cpu, %cpu, mem, %mem, rss, vsz, user, comm, time

Custom columns (-o): pid, ppid, user, %cpu, cpu, %mem, mem, vsz, rss, tty, stat, start, time, command, cmd, comm, args

PsEntry Properties

Each result is a PsBash.PsEntry object:

Property	Type	Description
PID	int	Process ID
PPID	int	Parent process ID
User	string	Username of the process owner
CPU	double	CPU usage percentage
Memory	double	Memory usage percentage
MemoryMB	double	Resident memory in megabytes
VSZ	long	Virtual memory size in KB
RSS	long	Resident set size in KB
TTY	string	Controlling terminal
Stat	string	Process state code
Start	DateTime	Process start time
Time	string	Cumulative CPU time (M:SS format)
Command	string	Command line
CommandLine	string	Full command line
ProcessName	string	Short process name
WorkingSet	long	Working set in bytes
BashText	string	Formatted text output line

Note

Cross-platform: on Linux, ps reads /proc directly for accurate data. On Windows and macOS, it uses .NET System.Diagnostics.Process with platform-specific enrichment (CIM on Windows, /bin/ps on macOS).

Examples

List all processes (BSD-style):

ps aux

root         1  0.0  0.1   2456  1024 ?       S     09:15     0:01 /sbin/init
you       1234  2.5  1.3  45600 13312 pts/0   Sl    10:30     1:42 pwsh

Top 5 processes by CPU usage:

ps aux | sort -k3 -rn | head 5

The output looks like text, but each result is still a PsEntry object. Properties survive the pipeline:

$top = ps aux | sort -k3 -rn | head 1
$top[0].PID         # 1234
$top[0].MemoryMB    # 13.0

Filter by user:

ps -u root

Filter by PID:

ps -p 1

Sort by memory descending:

ps aux --sort=-%mem

Custom column output:

ps -e -o pid,user,%cpu,%mem,command

    1 root      0.0  0.1 /sbin/init
 1234 you       2.5  1.3 pwsh

Access properties programmatically:

$procs = ps aux
$procs | Where-Object { $_.Memory -gt 1.0 } | ForEach-Object {
    '{0}: {1} MB' -f $_.ProcessName, $_.MemoryMB
}

---

env / printenv

Print environment variables as structured objects. Both env and printenv call the same function.

Syntax

env [VARNAME]
printenv [VARNAME]

When called with no arguments, lists all environment variables sorted by name. When called with a variable name, returns that single variable.

EnvEntry Properties

Each result is a PsBash.EnvEntry object:

Property	Type	Description
Name	string	Environment variable name
Value	string	Environment variable value
BashText	string	Formatted as NAME=VALUE

Examples

List all environment variables:

env

HOME=/home/you
PATH=/usr/bin:/bin
SHELL=/bin/bash

Get a specific variable:

env HOME

HOME=/home/you

Access the value programmatically:

$home = env HOME
$home.Value    # "/home/you"
$home.Name     # "HOME"

Filter environment variables with grep:

env | grep PATH

PATH=/usr/bin:/bin
MANPATH=/usr/share/man

Count environment variables:

env | wc -l

---

date

Print the current date and time, or format a specific date. Returns a DateOutput object with typed date components.

Syntax

date [OPTIONS] [+FORMAT]

Flags

Flag	Description
-d STRING / --date=STRING	Display time described by STRING instead of now
-u / --utc / --universal	Print in UTC
-r FILE / --reference=FILE	Display the last modification time of FILE
+FORMAT	Output format using % specifiers

Format Specifiers

Specifier	Description	Example
%Y	Four-digit year	2026
%m	Month (01-12)	04
%d	Day of month (01-31)	02
%H	Hour, 24-hour (00-23)	14
%M	Minute (00-59)	30
%S	Second (00-59)	45
%s	Seconds since Unix epoch	1775340645
%A	Full weekday name	Thursday
%B	Full month name	April
%Z	Timezone	UTC
%a	Abbreviated weekday	Thu
%b	Abbreviated month	Apr
%e	Day of month, space-padded	2
%j	Day of year (001-366)	092
%p	AM/PM	PM
%n	Newline
%t	Tab
%%	Literal %	%

DateOutput Properties

Each result is a PsBash.DateOutput object:

Property	Type	Description
Year	int	Four-digit year
Month	int	Month number (1-12)
Day	int	Day of month (1-31)
Hour	int	Hour (0-23)
Minute	int	Minute (0-59)
Second	int	Second (0-59)
Epoch	long	Unix timestamp (seconds since 1970-01-01)
DayOfWeek	string	Full weekday name
TimeZone	string	Timezone identifier
DateTime	DateTimeOffset	The underlying .NET DateTimeOffset
BashText	string	Formatted date string

Examples

Current date and time (default format):

date

Thu Apr  2 14:30:45 America/Chicago 2026

Custom format:

date '+%Y-%m-%d %H:%M:%S'

2026-04-02 14:30:45

Unix epoch timestamp:

date '+%s'

1775340645

Display a specific date:

date -d '2025-12-25'

Thu Dec 25 00:00:00 America/Chicago 2025

UTC output:

date -u

Thu Apr  2 19:30:45 UTC 2026

Last modification time of a file:

date -r package.json

Access properties programmatically:

$d = date
$d.Year       # 2026
$d.Epoch      # 1775340645
$d.DayOfWeek  # "Thursday"

---

hostname

Print the system hostname.

Syntax

hostname

Return Type

PsBash.TextOutput with a single property:

Property	Type	Description
BashText	string	The system hostname

Uses [System.Net.Dns]::GetHostName() for cross-platform compatibility.

Examples

Print the hostname:

hostname

my-workstation

Access the value programmatically:

$h = hostname
$h.BashText    # "my-workstation"

Use in a formatted string:

$user = whoami
$host = hostname
printf '%s@%s\n' $user.BashText $host.BashText

you@my-workstation

---

whoami

Print the current username.

Syntax

whoami

Return Type

PsBash.TextOutput with a single property:

Property	Type	Description
BashText	string	The current username

Uses [System.Environment]::UserName for cross-platform compatibility.

Examples

Print the current user:

whoami

you

Access the value programmatically:

$me = whoami
$me.BashText    # "you"

Combine with other commands:

ps -u (whoami).BashText

---

which

Locate a command by name. Returns the path to the executable or function definition.

Syntax

which [OPTIONS] NAME...

Flags

Flag	Description
-a	Show all matches, not just the first

WhichOutput Properties

Each result is a PsBash.WhichOutput object:

Property	Type	Description
Command	string	The command name that was looked up
Path	string	Resolved path or definition
Type	string	Command type (e.g., application, function, alias)
BashText	string	The resolved path

Examples

Locate a command:

which pwsh

/usr/bin/pwsh

Show all matches:

which -a python

/usr/bin/python
/usr/local/bin/python

Check the command type:

$w = which grep
$w.Type       # "alias"
$w.Path       # "Invoke-BashGrep"
$w.Command    # "grep"

Locate multiple commands:

which ls cat grep

Invoke-BashLs
Invoke-BashCat
Invoke-BashGrep

---

balias / unalias

Define, display, or remove shell aliases. The command is named balias to avoid conflicting with PowerShell’s built-in alias command. The unalias command is also available.

Syntax

balias [OPTIONS] [NAME[=VALUE]...]
unalias NAME...
unalias -a

Flags

Flag	Description
-p	List all aliases (same as calling balias with no arguments)
-u	Unalias mode (remove aliases)
-a	Remove all aliases (used with -u)

Note

The unalias command calls the same function as balias but you must use -u to trigger removal mode. Use balias -u NAME to remove a single alias, or balias -u -a to remove all aliases.

AliasOutput Properties

Each result is a PsBash.AliasOutput object:

Property	Type	Description
Name	string	Alias name
Value	string	Alias value (the command it expands to)
BashText	string	Formatted as alias name='value'

Examples

Define an alias:

balias ll='ls -la'

List all aliases:

balias

alias ll='ls -la'

Look up a specific alias:

balias ll

alias ll='ls -la'

Access properties programmatically:

balias mygrep='grep -rn'
$a = balias mygrep
$a.Name     # "mygrep"
$a.Value    # "grep -rn"

Remove an alias:

balias -u ll

Remove all aliases:

balias -u -a

---

time

Run a command and measure its execution time. Returns the command’s output along with timing information.

Syntax

time COMMAND [ARGS...]

TimeOutput Properties

Each result is a PsBash.TimeOutput object:

Property	Type	Description
RealTime	TimeSpan	Wall-clock elapsed time
Command	string	The command that was timed
ExitCode	int	Exit code of the command (0 = success)
BashText	string	The command’s text output

The real time is also printed to stderr in the format real 0.123s.

Examples

Time a command:

time ls -la

-rw-r--r-- 1 you you 141234 Apr  2 10:30 PsBash.psm1
real    0.045s

Access timing properties:

$t = time sleep 2
$t.RealTime.TotalSeconds    # ~2.0
$t.ExitCode                 # 0
$t.Command                  # "sleep"

Time a pipeline-producing command:

$t = time grep -r 'function' src/
$t.RealTime.TotalMilliseconds    # elapsed ms

---

sleep

Delay execution for a specified amount of time. Produces no output.

Syntax

sleep NUMBER[SUFFIX]...

Duration Suffixes

Suffix	Meaning	Example
s	Seconds (default)	sleep 5s
m	Minutes	sleep 2m
h	Hours	sleep 1h
d	Days	sleep 1d

When no suffix is given, the number is treated as seconds. Multiple arguments are summed together.

Examples

Sleep for 3 seconds:

sleep 3

Sleep for 500 milliseconds:

sleep 0.5

Sleep with a suffix:

sleep 2m

Combine multiple durations:

sleep 1m 30s

This sleeps for 90 seconds total (1 minute + 30 seconds).