Try: python3 -m http.server 8080 --bind 0.0.0.0 Info: Python's built-in HTTP server serves the current working directory over HTTP. --bind 0.0.0.0 makes it reachable across all network interfaces on port 8080. Examples: $ cd /path/to/share && python3 -m http.server 8000 # Share specific directory $ python3 -m http.server 8080 --directory /var/www/public […]
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Try: sudo debugfs -R 'lsdel' /dev/sda1 | tail -20 Info: debugfs is a low-level ext filesystem tool. lsdel lists deleted inodes, and dump <inode> <file> restores content. Works only if blocks haven't been overwritten yet. Examples: $ sudo debugfs /dev/sda1 # Interactive filesystem mode $ sudo extundelete --restore-all /dev/sda1 # Automated […]
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Try: sudo lvcreate --snapshot --name pre_upgrade_snap --size 10G /dev/ubuntu-vg/root Info: LVM snapshots capture the filesystem state at creation time. They use copy-on-write storage, recording changed blocks after the snapshot is created. A snapshot can later be merged to roll back changes. Examples: $ sudo lvcreate -s -n snap1 -L 5G /dev/vg0/mysql […]
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Try: find . -name '*.txt' -exec sh -c 'iconv -f WINDOWS-1252 -t UTF-8 "$1" -o "$1.utf8" && mv "$1.utf8" "$1"' _ {} \; Info: iconv converts text encodings (-f=from, -t=to). Wrapping in sh -c enables chaining iconv and mv per file. The _ acts as a placeholder for $0 in the […]
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Try: ss -ti | grep -A3 'ESTAB' | head -20 Info: ss -ti dumps TCP internal metrics. Look for retrans:X/Y (X current retransmits, Y total) and rtt (round-trip time). Non-zero retransmits signal packet loss or network congestion. Examples: $ ss -ti state established '( dport = :443 )' # Inspect HTTPS […]
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Try: sed -n '/BEGIN CERTIFICATE/,/END CERTIFICATE/p' /etc/ssl/certs/server.crt Info: sed -n suppresses automatic printing. The pattern '/START/,/END/p' prints all lines between two matching delimiters (inclusive). Examples: $ sed -n '/^\[database\]/,/^$/p' config.ini # Extract section until empty line $ awk '/BEGIN/,/END/' file.txt # Equivalent using awk $ sed -n '/ERROR/,+5p' logfile # Print […]
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Try: ./deploy.sh 2>&1 | tee -a deploy.log Info: tee splits stdout to both terminal and file. 2>&1 redirects stderr into stdout first to capture error logs. -a appends output instead of overwriting. Examples: $ ./script.sh 2>&1 | tee output.log # Overwrite log with output + errors $ make 2>&1 | tee […]
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Try: find /home/linuxteck -type f -exec md5sum {} + | sort | uniq -w32 -D Info: md5sum hashes file contents, sort groups identical hashes, and uniq -w32 -D compares the 32-character hash to output all duplicate files. Examples: $ find . -type f -exec md5sum {} + | sort | uniq […]
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Try: find /var/www -type f -newermt '2026-07-23 14:00:00' ! -newermt '2026-07-23 16:00:00' Info: -newermt 'DATE' matches files modified AFTER a timestamp. Combined with ! -newermt, it isolates files modified BETWEEN two specific times, making it useful for forensic analysis. Examples: $ find / -newermt '1 hour ago' -type f 2>/dev/null # […]
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Try: ssh -L 3307:db-internal:3306 -N -f linuxteck@jumphost Info: -L local_port:target_host:target_port forwards local traffic through SSH to a remote server. -N skips the remote shell, and -f sends SSH to the background. Examples: $ ssh -L 8080:localhost:80 user@server # Access remote web app locally $ ssh -R 9000:localhost:9000 user@server # Expose local […]
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Try: sudo systemctl edit --force --full myapp.service Info: Restart=on-failure restarts the app after a non-zero exit or crash, while RestartSec adds a delay before restarting. StartLimitBurst and StartLimitIntervalSec help prevent a service from repeatedly restarting in a crash loop. Examples: $ sudo systemctl status myapp # View service status $ sudo […]
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Try: ionice -c 3 -p $$ Info: ionice sets I/O priority. Class 3 (idle) only allows disk access when no other process needs it. Examples: $ ionice -c 3 nice -n 19 rsync -av /src /dst # Throttles CPU + I/O $ ionice -c 2 -n 7 tar -czf backup.tar.gz /data […]
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Try: mtr -rw -c 20 google.com Info: mtr combines traceroute and ping. -r enables report mode, -w shows full hostnames, and -c 20 sends 20 pings per hop. Examples: $ mtr google.com # Interactive real-time mode $ mtr --tcp -P 443 google.com # TCP mode on port 443 $ mtr -j […]
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Try: ssh-keygen -t ed25519 -a 100 -f ~/.ssh/id_ed25519 -C "linuxteck@ubuntu-2026" Info: Ed25519 provides faster, more secure keys than RSA. -a 100 increases KDF rounds to strengthen passphrase protection against offline brute-forcing. Examples: $ ssh-copy-id -i ~/.ssh/id_ed25519.pub user@server # Copy public key to server $ ssh-keygen -y -f ~/.ssh/id_ed25519 # Print public […]
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Try: iperf3 -c 192.168.1.100 Info: iperf3 measures real TCP/UDP throughput. Run iperf3 -s on the server and iperf3 -c <SERVER_IP> on the client. Examples: $ iperf3 -s # Server mode (run first) $ iperf3 -c server -u -b 1G # UDP test at 1 Gbps $ iperf3 -c server -R # […]
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Try: openssl enc -aes-256-cbc -pbkdf2 -in secrets.txt -out secrets.enc Info: AES-256-CBC provides strong symmetric encryption. -pbkdf2 uses secure key derivation (automatically adding a salt) to prevent brute-force attacks. Examples: $ openssl enc -d -aes-256-cbc -pbkdf2 -in secrets.enc -out secrets.txt # Decrypt $ tar -czf - /home/data | openssl enc -aes-256-cbc -pbkdf2 […]
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