set -euo pipefail across all four, but added deliberately rather than pasted in -- each script needed the places where a non-zero exit is normal handled first, or strict mode would have made them worse: - sys_monitor / process_monitor: `ps | head -n 6` is a latent SIGPIPE. head closes the pipe after six lines, and on a host with enough processes ps fills the buffer and exits 141, which pipefail turns into a script abort -- on exactly the busy machine you wanted to inspect. Confirmed the mechanism (a large producer into head returns 141) and those pipelines now tolerate it. - security_audit: find exits non-zero when it cannot read a directory, which is routine when walking the whole filesystem. Without handling, set -e aborted the audit part way while still looking complete. Also notes that a clean report as non-root means little, since find cannot descend where it may not read. - network_info: iptables needs root, so the last section aborted the script for ordinary users. Now reports the failure, and falls back to nft where iptables is absent. process_monitor also no longer kills on sight. `pkill -x` by name can match several processes at once, and as root that is an easy way to take down more than intended. It now prints what it matched and asks, with FORCE=1 for unattended use and a refusal rather than a hang when there is no tty. All four run clean; the kill path was tested against a live process and left it alive.
62 lines
2.2 KiB
Bash
62 lines
2.2 KiB
Bash
#!/bin/bash
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# network_info.sh - Show network interfaces, routes, open ports, firewall rules
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#
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# Copyright (C) 2025 LINUXexpert.org
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#
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# This program is free software: you can redistribute it and/or modify it
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# under the terms of the GNU General Public License as published by the
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# Free Software Foundation, version 3 of the License.
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#
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# This program is distributed in the hope that it will be useful, but
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# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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# or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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# for more details.
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#
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# You should have received a copy of the GNU General Public License along
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# with this program. If not, see <https://www.gnu.org/licenses/>.
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#
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# Usage: network_info.sh (no arguments)
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# Description: Displays network interface addresses, routing table, open ports, and iptables rules.
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#
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# Read-only. The iptables section needs root; without it that section
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# reports the failure rather than silently showing nothing.
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set -euo pipefail
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echo "==== Network Interfaces (IP addresses) ===="
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if command -v ip &> /dev/null; then
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ip -brief addr show # brief output of interfaces and addresses
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elif command -v ifconfig &> /dev/null; then
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ifconfig -a
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else
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echo "No network interface tool (ip or ifconfig) available."
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fi
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echo -e "\n==== Routing Table ===="
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if command -v ip &> /dev/null; then
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ip route show
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elif command -v route &> /dev/null; then
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route -n
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else
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echo "No routing tool (ip or route) available."
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fi
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echo -e "\n==== Listening Ports (TCP/UDP) ===="
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if command -v ss &> /dev/null; then
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ss -tulwn # show TCP/UDP ports in listen state with numeric addresses
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elif command -v netstat &> /dev/null; then
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netstat -tuln
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else
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echo "No socket listing tool (ss or netstat) available."
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fi
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echo -e "\n==== Firewall Rules (iptables) ===="
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if command -v iptables &> /dev/null; then
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# Needs root; report the failure instead of letting set -e abort here.
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iptables -L -n -v || echo "Could not read iptables rules (run as root?)."
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elif command -v nft &> /dev/null; then
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nft list ruleset || echo "Could not read nftables ruleset (run as root?)."
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else
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echo "iptables command not found (no firewall rules to show or using nftables)."
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fi
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