View source for Notepad:Linux

= Linux Tips and Tricks =
Linux stuff I often have to lookup. Just my personal list of things.

* [[Notepad:NFS unload| NFS unload filesystem]]
* [[Notepad:mysql slave skip error| mysql slave skip error]]
* [[Notepad:GRUB install| GRUB install]]
* [http://www.enterux.com/en/resources/yahoo-domainkeys-howto-debian Domain Keys]
* [[Notepad:Change Timezone| Change Timezone]]
* [http://datatag.web.cern.ch/datatag/howto/tcp.html Gigabit Network]
* [[Notepad:Syncookie| Syncookie]]
* [[Notepad:Local Mount| Local Mount]]
* [[Notepad:SWAP| SWAP]]
* [[Notepad:depmod| depmod]]
* [[Notepad:Chain of IP addresses| Chain of IP addresses]]
* [[Notepad:Xterm startup|Xterm startup]] with different colors and font sizes
* [[Notepad:RPM - YUM Platform]]
* [http://fedoraproject.org/wiki/YumUpgradeFaq In place upgrade of Fedora Core by yum]
* [http://www.cyberciti.biz/tips/rhel-centos-fedora-linux-iscsi-howto.html CentOS / Red Hat Linux: Install and manage iSCSI Volume]
* [https://www.certdepot.net/rhel7-configure-ldap-directory-service-user-connection/ Configure a LDAP directory service ]
* [[Notepad:NetworkManager Configuration| NetworkManager Configuration]]
* [http://bobpeers.com/technical/telnet_imap Accessing IMAP email accounts using telnet.]
* Enable service syslog to have /var/log/messages populated
* Force a disk check on reboot 
 shutdown -rF now
* [http://www.rootninja.com/create-a-network-bridge-for-virtual-machines/ Create a network bridge for Virtual Machines]
* [http://www.rfxn.com/upgrade-centos-4-to-5/ Upgrade CentOS 4 to 5]
* [[Notepad:SSL CRT generation | Create a CRT for an SSL certificate]]
* [[Notepad:Samba | Properly configure Samba on Linux]]
* [[Notepad:Postfix | Postfix config]]
* [[Notepad:wget | Use wget to download full website]]
* [http://manuel.kiessling.net/2013/03/19/converting-a-running-physical-machine-to-a-kvm-virtual-machine/ Converting a running physical machine to a kvm virtual machine]
* Generate XAUTH on a new host
 xauth add `hostname`/unix:0 . `openssl rand -hex 32`
* yum versionlock - allows to lock an rpm
* install faster random for dns etc. 
<syntaxhighlight lang='bash' line>
 yum install haveged;
 systemctl enable haveged;
 systemctl start haveged
</syntaxhighlight>
* [https://askubuntu.com/questions/73864/how-to-modify-an-invalid-etc-sudoers-file How to modify an invalud sudoers file]
 sudo visudo -f /mnt/etc/sudoers
* [http://manuel.kiessling.net/2013/03/19/converting-a-running-physical-machine-to-a-kvm-virtual-machine/ Converting a running physical machine into a KVM virtual machine]
* Which Process is listening on a port
 netstat -tulpn
* [https://www.unixarena.com/2018/05/how-to-recover-grub-on-rhel-7-centos-7.html/ Recover GRUB 2]
* Install all package from another machine
 xargs yum -y install < file
* Create Default Home Directory
 mkhomedir_helper username
* [[Notepad:crontab | Schedule crontab with lock]]
* [https://hackernoon.com/how-to-shutdown-your-servers-in-case-of-power-failure-ups-nut-co-34d22a08e92 Configure UPS shutdown frmo Linux with nut]
* [[Notepad:mc | Midnight Commander]]
* [[Notepad:nagios | Nagios]]
* [https://wiki.archlinux.org/index.php/Google_Authenticator Google Authenticator Setup]
* [https://www.svennd.be/software-raid-1-on-centos-7-eufi-running-system/ Boot from Centos 7 RAID 1 EUFI]
* [https://serverfault.com/questions/779634/create-a-directory-under-var-run-at-boot Create a directory under var at boot or startup]
 use tmpfiles.d and have your package create at startup or boot a file or directory /usr/lib/tmpfiles.d/mydaemon.conf :
 man tmpfiles.d
 
 #Type Path            Mode UID      GID    Age Argument
 d     /run/mydaemon   0755 myuser myuser   -   -

* [https://wiki.archlinux.org/index.php/Lm_sensors lm_sensors]
* [https://unix.stackexchange.com/questions/227017/how-to-change-systemd-service-timeout-value Change systemd Timeout]
* [https://jumpcloud.com/blog/sharing-google-authenticator-secret-keys-across-servers/ Google Authenticator Across Servers]
* Yum install with missing deps
 rpm -Uvh --nodeps $(repoquery --location <module>)
* [[Notepad:LVM Snapshot| LVM Snapshot]]
* [https://www.linuxquestions.org/questions/slackware-14/how-to-configure-iptables-for-router-with-2-public-ip-addresses-4175618196/ Example routing iptables firewall]
* [[Notepad:Disable IPv6 | Disable IPv6]]
* [https://serverfault.com/questions/620019/smartctl-megaraid-how-to-find-the-right-device-node-for-an-adapter find the right device for smartctl]
* ssh into a machine without a terminal '''<nowiki>-T</nowiki>'''
* [https://unix.stackexchange.com/questions/620427/how-to-detect-and-clean-up-junk-journal-files Clean Out Journal]
   sudo journalctl --vacuum-time=3weeks
* [https://www.jamescoyle.net/how-to/323-reclaim-disk-space-from-a-sparse-image-file-qcow2-vmdk Reclaim disk space from a sparse image file (qcow2/ vmdk)]
* [https://medium.com/swlh/make-your-raspberry-pi-file-system-read-only-raspbian-buster-c558694de79 Make your Raspberry Pi file system read-only]
* [https://unix.stackexchange.com/questions/87990/linux-as-router-with-multiple-internet-providers Linux Multiple Interface NAT]
* Get Ethernet Address of network (Exclude lo, virtual and ethernet)
   ip -br l | awk '$1 !~ "lo|vir|eth" { print $3 }'

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