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Linux Survival Basics

Read-only

Show Linux Route Table

You need the current route table and default gateway.

Command

ip route

Before you run this

System impact: Read-only. Low when scoped to the shown target.

When not to use it: Do not add routes before checking interface and NetworkManager state.

Expected output

Routes including `default via ...` when a default route exists.

System impact

Read-only. Nothing changes. The command reads current state and prints diagnostic evidence.

Recovery / rollback: no state is changed.

When to use it

Use when a host has network but cannot reach outside networks.

When not to use it

Do not add routes before checking interface and NetworkManager state.

Example run

Commands shown

These are the commands shown for inspection. Treat them as an example, not proof that your system will behave identically.

  1. ip route
  2. ip route

next steps

Related commands

Linux Survival Basics Read-only

Show Failed Mount Units

systemd often records mount failures as failed units.

systemctl --failed --no-pager
Linux Survival Basics Sensitive output

Show Recent Server Reboots

Confirm whether the server actually rebooted and when.

last -x reboot | head -5
Linux Survival Basics Read-only

Show the Real User Cron Jobs

Cron problems often hide behind comments, blank lines, and copied folklore.

crontab -l | sed -n '/^[[:space:]]*#/d;/^[[:space:]]*$/d;p'

next diagnostic step

Where to go from this command

Study mapping

Use this as independent command practice: read the notes, predict the output, then compare it with the example before using a real shell.

  • LPIC-1 style command-line practice
  • LFCS style performance-task practice

Independent study support only. No affiliation, endorsement, exam dumps, or real exam questions.