apachectl sudo apache2ctl -M (show all loaded modules) | sudo apache2ctl -D DUMP_RUN_CFG | sudo apache2ctl -D DUMP_VHOSTS | sudo apache2ctl -S (show parsed VHost settings) | sudo apachectl -t (apache config test) | apt apt-cache search php7.3 | apt-cache show php7.3 install pkgs “kept back”: sudo apt-get dist-upgrade | sudo apt-get --with-new-pkgs upgrade | Clean up partial package: sudo apt autoclean Clean up apt cache: sudo apt-get clean Clean up unused dependencies: sudo apt autoremove Uninstall application: sudo apt autoremove application-name apt list --installed | grep " installed" /var/log/dpkg.log (also log.1) | apt show <pkg> | apt purge <unneeded package> | sudo apt-mark showhold | sudo apt-mark unhold package_name | sudo apt autoremove | sudo apt autoclean | sudo apt-get remove --purge $(dpkg -l | grep "^rc" | awk '{print $2}') remove rc residual packages awk awk '{print $5}' | grep -Eo '([0-9]{1,3}\.){3}[0-9]{1,3}'| sort cat cat papers_to_read.htm | sort | cut -c 1-50 | uniq -d (find duplicate lines) chmod chmod --reference=reference_file file [f2 f3] | chown chown --reference=reference_file file [f2]f3 | comm comm -12 <(sort file1.txt) <(sort file2.txt) find common lines in two files cp sudo cp -p pedit.html blogview.html [cp -rp doc] | cp preserving ownership, permissions curl curl cheat.sh/find | curl ifconfig.io | curl ipinfo.io | curl http://ipv4.icanhazip.com or curl http://icanhazip.com or curl http://ip.fossdaily.xyz | curl --ssl | curl --insecure | curl -I http://domain.com (headers info) | article | curl cookbook | dig dig example.com ANY +noall +answer dpkg dpkg -l | grep "^rc" | sudo apt-get remove --purge $(dpkg -l | grep "^rc" | awk '{print $2}') find find . -maxdepth 1 -type f -name "*.md" -exec ls -al {} \; | find /tmp -type f -name ".htaccess" -exec grep -EHi '(Redirect|RewriteRule)' {} \; | find . -type f -perm 777 -exec chmod 644 {} \; | find /home -type d -perm -o+w -exec ls -ld {} \; find world-writable directories in /home gpg gpg --output outfile.gpg --symmetric --cipher-algo AES256 file.ext | gpg -o original_file.txt -d file.txt.gpg | grep grep -Eri '(Redirect|RewriteRule)' /etc/apache2/ iptables sudo iptables -L | sudo iptables-save >iptables.rules | sudo iptables-restore <iptables.rules | ubuntu iptables doc | journalctl journalctl -u ssh.service | journalctl -u network.service | journalctl article | ls ls -H (follow symbolic links) | ls -Al | tr -s ' ' | cut -f9- -d' ' (list just file and folder names; -R for dir recursion) netstat netstat -tulpn | netstat -npl | netstat -tulpn | netstat -npl | netstat -plane | grep :80 | awk '{print $5}' | grep -Eo '([0-9]{1,3}\.){3}[0-9]{1,3}' | sort | uniq -c | sort -n conn port 80 perl perl -pi -e 's,RoseHosting,BestManagedVPS' file.php Replace all string instances w/o opening file w text editor pscp pscp -agent -i <keyfile> -P <port> (-agent is for pageant) sed sed -e "s/\r//g" file > newfile remove newline chars from file | sed -i 's/search/repace/g' *.php replace string in all specified files | systemctl sudo systemctl restart apache2 | sudo systemctl -a | sudo systemctl --state active | sudo systemctl list-timers | sudo systemctl list-unit-files | sudo systemctl list-unit-files | grep -i docker | sudo systemctl | grep running (list running services) | sudo systemctl list-unit-files | grep enabled (list enabled services) | sudo systemctl reload ssh.service | systemctl list-unit-files --type=service | systemctl list-dependencies graphical.target | article | sudo systemctl enable apache2 | sudo systemctl disable apache2 | sudo systemctl is-enabled apache2 | article | tar tar -cvzf archive-name.tar.gz directory-name | tar -C /diff-folder -xvf yourfile.tar to extract to a different directory | timedatectl timedatectl | Bash date to/from unix epoch time: date +%s | date -d @<unix epoch time> | vim :w !sudo tee % | :set ignorecase | :set ff=unix or :set ff=dos | :set number or :set nonumber | :nohl |

df -h | df -T du -sh dpkg-query -L <package name> (list files in package) faillog | free | history -c host ipaddr|domain (Cloud Shell: get ip addr for domain or domain for ip addr, etc) hostnamectl status id <username> sudo iptables -L -nv --line-numbers | sudo iptables-restore < /etc/iptables/rules.v4 | lastlog | last sudo lshw sudo sshd -T | /etc/ssh/sshd_config | ssh security hardening | lsb_release -a | cat /proc/version wget --no-check-certificate whatis zgrep -E "^(Remove:|Purge)" /var/log/apt/history.log* sudo -u www-data php occ app:list zip -d gallery.zip "picture_43_9.jpg" (delete file from zip, note zip goes first, followed by file)

gcloud info | gcloud version | Windows: netstat | findstr ESTABLISHED

Replace string recursively with find and sed Remove all dpkg rc residual packages

delete every line until PATTERN, that line included: cat index.html | sed '1,/body onload/d' print (p) from the first line matching PATTERN to the end ($): cat index.html | sed -n '/body onload/,$p'

Which Linux distro is running: cat /etc/*-release

101 Bash Commands | Text Processing in the Shell | Mastering File And Text Manipulation With Awk Utility

dpkg queries:

-l, --list package-name-pattern...
    List packages matching given pattern.
-s, --status package-name...
    Report status of specified package.
-L, --listfiles package-name...
    List files installed to your system from package-name.
-S, --search filename-search-pattern...
    Search for a filename from installed packages.
-p, --print-avail package-name...
    On debian/ubuntu, use instead: apt-cache show package-name
    Display details about package-name, as found in /var/lib/dpkg/available. 

Useful network commands, labnol Basic regex in javascript

/etc/alternatives (e.g., php cli version, check vs apache version)

what process(es) are running for port 443: sudo lsof -t -i:443

journalctl — query the systemd journal. Systemd has its own logging system called the journal.  To read those logs, journalctl is used. The journal (journald) stores log data in binary format, unlike past services that stored logs in plain text. As such, journalctl is used to transmute binary logs into readable plain text. Check out The ultimate guide to using journalctl. Another good read is kmsg. Kmsg (/dev/kmsg) is a file stored in the Linux filesystem, used to store messages from the Kernel, and is used by dmesg and klogd.

Linux Commands frequently used by Linux Sysadmins – Part 5

How to manage background processes in Linux

cheatsheet for ip commands #network #linux