Shell Behavior

Detailed documentation of CLI shell features and behavior.

Modes

The CLI operates in two modes, mirroring JunOS/VyOS conventions:

Operational Mode (abng>)

Purpose: View system state, monitor events, execute operational requests

Prompt: abng>

Available commands:

• show — Display operational state
• configure — Enter configuration mode
• monitor — Real-time event monitoring
• request — Execute operational requests
• ping — Ping from BNG
• traceroute — Traceroute from BNG
• quit — Exit CLI
• ? or help — Show help

Example:

abng> show subscribers
abng> monitor subscribers
abng> request subscriber disconnect 1
abng> quit

Configuration Mode (abng#)

Purpose: Modify the candidate configuration

Prompt: abng#

Available commands:

• set — Add or modify configuration
• delete — Remove configuration
• show — Display candidate configuration
• show | compare — Show diff vs running config
• commit — Apply candidate to running config
• commit confirmed <minutes> — Apply with auto-rollback
• rollback <n> — Revert to archived config
• discard — Discard candidate changes
• exit — Return to operational mode
• ? or help — Show help

Example:

abng# set pppoe enabled true
abng# set pppoe ac_name "AthenaBNG"
abng# show | compare
abng# commit
abng# exit

Navigation Keys

Key	Action
Tab	Auto-complete current word
Shift+Tab	Reverse auto-complete
↑	Previous command in history
↓	Next command in history
Ctrl+A	Move to start of line
Ctrl+E	Move to end of line
Ctrl+K	Delete from cursor to end of line
Ctrl+U	Delete from start of line to cursor
Ctrl+C	Cancel current input (does not exit)
Ctrl+D	Exit CLI
Backspace	Delete character before cursor
Delete	Delete character at cursor

Command History

History is persisted to ~/.abng_history with the following behavior:

• Max entries: 1000
• Ignore space: Commands starting with a space are not saved
• Persistence: History is saved when exiting the CLI
• Loading: History is loaded when starting the CLI

Example:

# This command is saved
abng> show subscribers

# This command is NOT saved (starts with space)
abng>  show subscribers

# View history file
cat ~/.abng_history

Tab Completion

Tab completion is context-aware and works at every level:

Operational Mode Completion

abng> show <TAB>
subscribers  interfaces  vlans  routes  bgp  ospf  qos  system  configuration  version

abng> show subscribers <TAB>
detail  pppoe  dhcp  summary

abng> show subscribers detail <TAB>
<session_id>

abng> request <TAB>
subscriber  radius  system

abng> request subscriber <TAB>
disconnect

abng> request subscriber disconnect <TAB>
<session_id>  interface

Configuration Mode Completion

abng# set <TAB>
system  interfaces  demux  pppoe  dhcp  radius  qos  cgnat  routing  api  snmp  monitoring

abng# set system <TAB>
hostname  router_id  timezone  log_level  log_format  ntp_servers  dns_servers

abng# set pppoe <TAB>
enabled  ac_name  mtu  mru  lcp_echo_interval  lcp_echo_failure

abng# delete <TAB>
system  interfaces  demux  pppoe  dhcp  radius  qos  cgnat  routing  api  snmp  monitoring

Context Help

Type ? or help to see available commands:

abng> ?
Available commands:
  show          Show operational state
  configure     Enter configuration mode
  monitor       Real-time monitoring
  request       Execute operational requests
  ping          Ping from BNG
  traceroute    Traceroute from BNG
  quit          Exit CLI

Type a partial command followed by ? to see available options:

abng> show?
Possible completions:
  subscribers            Show active subscriber sessions
  interfaces             Show network interfaces
  vlans                  Show dynamic VLAN interfaces
  routes                 Show routing table
  bgp                    Show BGP state
  ospf                   Show OSPF state
  qos                    Show QoS/CAKE status
  system                 Show system information
  configuration          Show running configuration
  version                Show software version

abng> show subscribers?
Possible completions:
  detail                 Show detailed subscriber info
  pppoe                  Show PPPoE sessions only
  dhcp                   Show DHCP sessions only
  summary                Show session count summary

Pipe Filters

Pipe filters allow you to filter and format output:

abng> show subscribers | match user1
abng> show subscribers | count
abng> show subscribers | no-more
abng> show subscribers | save /tmp/subscribers.txt

Available filters:

• match <regex> — Filter lines matching regex
• count — Count matching lines
• no-more — Disable pager (show all output without pausing)
• save <file> — Save output to file

Pager Behavior

Long output is automatically paged using less:

abng> show configuration
(output is paged)
-- More -- (press space to continue, q to quit)

To disable paging:

abng> show configuration | no-more

Error Handling

Connection Errors

If abngd is not running:

Error: cannot connect to abngd — is abngd running?

Solution:

sudo systemctl start abngd

Command Syntax Errors

Error: unknown command: 'show foo'. Type '?' for help.

Solution: Use tab completion or ? to see available commands.

Configuration Validation Errors

Validation error: invalid IP address: "not-an-ip"

Solution: Check the configuration syntax and try again.

Non-Interactive Mode

Execute a single command without entering the interactive shell:

/opt/athena-bng/bin/abng -c "show subscribers"
/opt/athena-bng/bin/abng -c "show system"
/opt/athena-bng/bin/abng -c "show configuration | no-more"

Use cases:

• Scripting and automation
• Integration with monitoring systems
• One-off queries

Exiting the CLI

From Operational Mode

abng> quit

Or press Ctrl+D.

From Configuration Mode

abng# exit
abng>

Then:

abng> quit

Or press Ctrl+D twice.

Tips and Tricks

Save Output to File

abng> show subscribers | save /tmp/subscribers.txt

Filter Output

abng> show subscribers | match "pppoe"
abng> show configuration | match "radius"

Count Results

abng> show subscribers | count
Count: 42

Disable Pager

abng> show configuration | no-more

View Command History

cat ~/.abng_history

Clear Command History

rm ~/.abng_history

Next Steps

• Operational Mode — All show and request commands
• Configuration Mode — All set, delete, commit commands
• Pipe Filters — Filter and format output