Linux Quick Reference Guide 8th edition January 2020 Foreword This guide stems from the notes I have been taking while studying and working as a Linux sysadmin and engineer. It contains useful information about standards and tools for Linux system administration, as well as a good amount of topics from the certification exams LPIC-1 (Linux Professional Institute Certification level 1), LPIC-2, RHCSA (Red Hat Certified System Administrator), and RHCE (Red Hat Certified Engineer). Unless otherwise specified, the shell of reference is Bash. This is an independent publication and is not affiliated with LPI or Red Hat. You can freely use and share the whole guide or the single pages, provided that you distribute them unmodified and not for profit. This document has been composed with Apache OpenOffice. Happy Linux hacking, Daniele Raffo Version history 1st edition May 2013 2nd edition September 2014 3rd edition July 2015 4th edition June 2016 5th edition September 2017 6th edition August 2018 7th edition May 2019 8th edition January 2020 Bibliography and suggested readings ● Evi Nemeth et al., UNIX and Linux System Administration Handbook, O'Reilly ● Rebecca Thomas et al., Advanced Programmer's Guide to Unix System V, McGraw-Hill ● Mendel Cooper, Advanced Bash-Scripting Guide, http://tldp.org/LDP/abs/html ● Adam Haeder et al., LPI Linux Certification in a Nutshell, O'Reilly ● Heinrich W. Klöpping et al., The LPIC-2 Exam Prep, http://lpic2.unix.nl ● Michael Jang, RHCSA/RHCE Red Hat Linux Certification Study Guide, McGraw-Hill ● Asghar Ghori, RHCSA & RHCE RHEL 7: Training and Exam Preparation Guide, Lightning Source Inc. ● Colin Barschel, Unix Toolbox, http://cb.vu/unixtoolbox.xhtml ● Ellen Siever et al., Linux in a Nutshell, O'Reilly, http://archive.oreilly.com/linux/cmd ● Christoph Braun, Unix System Security Essentials, Addison-Wesley ● Bruce Barnett, The Grymoire, http://www.grymoire.com/Unix ● Brendan Gregg, Linux performance, http://www.brendangregg.com/linuxperf.html ● Linus Torvalds' Linux documentation, https://github.com/torvalds/linux/tree/master/Documentation ● RHEL manuals, https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux ● A-Z index of Bash command line, http://ss64.com/bash ● GNU software manuals, http://www.gnu.org/manual ● Shell command line snippets, http://www.commandlinefu.com ● Bash command line snippets, http://www.bashoneliners.com ● RAM management in Linux, http://www.linuxatemyram.com ● Regular expressions tester, http://www.regextester.com ● Bash pitfalls, http://mywiki.wooledge.org/BashPitfalls ● Linux man pages, https://www.kernel.org/doc/man-pages ● CentOS 7 man pages, https://www.unix.com/man-page-centos-repository.php Index LVM................................................1 SQL..............................................64 SSH tools....................................127 LVM commands................................2 SQL SELECT..................................65 SSH operations............................128 System boot....................................3 SQL JOIN......................................66 SSH configuration.........................129 SysV startup sequence.....................4 MySQL..........................................67 X.509..........................................130 Login..............................................5 MySQL tools..................................68 OpenSSL.....................................131 Runlevels........................................6 MySQL syntax................................69 CA.pl..........................................132 SysV service management................7 MySQL status................................70 GnuPG........................................133 Systemd service management...........8 MySQL recipes...............................71 OpenVPN.....................................134 /etc/inittab......................................9 MySQL operations..........................72 Security tools...............................135 Filesystem Hierarchy Standard.........10 PostgreSQL...................................73 Key bindings - terminal.................136 Partitions and filesystem.................11 X..................................................74 Key bindings - X Window...............137 mount..........................................12 X tools..........................................75 udev...........................................138 Filesystem types............................13 X keysim codes..............................76 Kernel.........................................139 Swap............................................14 /etc/passwd...................................77 Kernel management......................140 /etc/fstab......................................15 User management..........................78 Kernel compile and patching..........141 Filesystem operations.....................16 Group management........................79 Kernel modules............................142 Filesystem maintenance..................17 UID and GID..................................80 /proc..........................................143 XFS, ReiserFS, CD-ROM fs...............18 sudo and su...................................81 /dev...........................................144 AutoFS..........................................19 Terminals......................................82 System recovery..........................145 RAID............................................20 Messaging.....................................83 DNS............................................146 Bootloader....................................21 cron.............................................84 DNS configuration.........................147 GRUB 2 configuration......................22 at.................................................85 DNS zone file...............................148 GRUB 2 operations.........................23 Utilities.........................................86 HTTP response codes....................149 GRUB Legacy.................................24 Localization...................................87 Apache........................................150 dpkg and apt.................................25 System time..................................88 Apache server configuration...........151 rpm..............................................26 syslog...........................................89 Apache main configuration.............152 yum.............................................27 E-mail...........................................90 Apache virtual hosts.....................153 yum repositories............................28 SMTP............................................91 Apache authorization....................154 Backup.........................................29 Sendmail.......................................92 Apache SSL/TLS...........................155 Archive formats..............................30 Exim.............................................93 Apache proxy...............................156 Documentation..............................31 Postfix..........................................94 Tomcat........................................157 Shell usage...................................32 Postfix configuration.......................95 Samba server..............................158 Text filters.....................................33 Procmail........................................96 Samba client................................159 Advanced text filters.......................34 Courier POP configuration................97 Samba global configuration............160 Regular expressions........................35 Courier IMAP configuration..............98 Samba share configuration............161 File management...........................36 Dovecot........................................99 Samba access configuration...........162 Directory management...................37 Dovecot mailbox configuration........100 Samba setup...............................163 File operations...............................38 Dovecot POP/IMAP configuration.....101 NFS............................................164 I/O streams...................................39 Dovecot authentication..................102 /etc/exports.................................165 read and echo................................40 FTP.............................................103 NFS setup....................................166 Processes......................................41 vsftpd.........................................104 iSCSI..........................................167 Signals.........................................42 CUPS..........................................105 iSCSI setup.................................168 Resource monitoring.......................43 IP addressing...............................106 DHCP..........................................169 vmstat..........................................44 Subnetting...................................107 PAM............................................170 free..............................................45 Network services..........................108 LDAP..........................................171 File permissions.............................46 Network configuration commands...109 ldapsearch...................................172 File attributes................................47 Network configuration files.............110 OpenLDAP...................................173 ACLs.............................................48 Red Hat vs Debian network config...111 SELinux.......................................174 Links............................................49