Configuring cups client lpstar and lpr commands Check if cups-client or cups-utils # zypper in cups-client # lpstat -p -v # telnet <PrinterIP> 9100 # lpstat -p <printer_name> -l # lpq -a # lpstat -ato From a network printer, print the file and check for idle state of the printer # ..
Boot the server in emergency mode with root password. Dryrun will give you information on how many sectors are affected and how may fix will happen. # fsck -N <Device Name> Perform FSCK, handle with care # fsck -p <Device Name> Make you always have backup before performing this activity, reboot the ..
Find the disk with stripes # lvs -o+lv_layout,stripes # lvs +o+devices,lv_layout,stripes # pvs | grep vg_volgroup002 # lsblk | grep '<disks which are present in VG or affected by LV>' All the striped disk must extend equally # pvresize /dev/sdp /dev/sdq # vgs # lvresize -L+200G /dev/vg_volgroup002/lv_mylv # resize2fs /dev/vg_volgroup002/lv_mylv once the disk is ..
To copy hidden files, you must include --include # rsync -av --include='.*' /opt/bluff/* /opt/linux/. If you are not using "*" and "." at the end rsync will copy hidden files # rsync -av --include='.*' /opt/bluff/ /opt/linux/ Below are few examples of rsync # rsync -axHAX --progress --stats /opt/bluff/* /opt/linux/. # rsync ..
Please be careful what you are doing, this can break you server or machine sometimes the kernel might have updated but initramfs would have been broken, in such condition dracut -kver can be used # dracut --kver 4.8.x.x86_64 Quick way to build initramfs for a specific kernel version is to invoke dracut ..
Reboot system and stop auto fsck on-boot # shutdown -rf now During boot press e and add fastboot # /vmlinuz-.xx ro root=LABEL=/ console=tty0 console=ttyS1,19200n8 fastboot press e during server boot and add fastboot at end of the boot kernel to skip fsck or avoid filesystem check during boot. To avoid filesystem check permenantly, ..
When you make changes in /etc/default/grub run below command to update /boot/grub2/grub.cfg # cat /etc/default/grub GRUB_HIDDEN_TIMEOUT=0 GRUB_TIMEOUT=20 Once you change timeout or add any additional parameter in CMDLINE # grub2-mkconfig -o /boot/grub2/grub.cfg why do we edit /etc/default/grub? Changes or edit in grub.cfg will be lost anytime when grub2-mkconfig is ..
check dns using dig or nslookup # dig w3calculator.com # nslookup techbluff.com Check the connectivity of a domain or by resolving the domain with DNS Server # nslookup myhostname <DNS-server-IP> # dig domainname.com @DNSServerIP How to check NS and SOA # dig NS @<DNS-Server-IP> w3calculator.com # dig SOA @<DNS-Server-IP> ..
Before deleting a blockdevice make sure to backup/snapshot of the disk check if the disk is mounted or added in any logical volume. # pvs | grep vg_1-lv-backup # fdisk -l | grep -i /dev/mapper/vg_1-lv-backup # lvremove /dev/mapper/vg_1-lv-backup # vgremove vg_1 # pvremove /dev/sde Finding LUN in azure # vgs # pvs ..
By using below commands, collect required disk information and mount points # df -hT # fdisk -l # lvdisplay # pvdisplay # lvs # lsblk -o NAME,KNAME,MAJ:MIN,FSTYPE,MOUNTPOINT # lsblk -o NAME,KNAME,MAJ:MIN,FSTYPE,MOUNTPOINT | egrep 'dm-0|dm-1' Once you see new disk visible on OS, create and mount swap disk using swapon ..
Sometime if blockdevice is not visible to OS # systemctl daemon-reload Enable a service on boot # systemctl is-active <servicename> # systemctl is-enabled <service_name> # systemctl enable <service_name> ..
zypper commands # zypper se -s 'kernel-def' | grep '4.12' # zypper wp libc.s0.6 # zypper se --provides --match-exact 'libc.so.6' # zypper in package-name +i installed by user request i installed automatically (by the resolver, see section Automatically installed packages) se - search package in - install package ..
Below are few frequently used commands for my application troubleshooting Check IP tables # iptables -t nat -nL Check how many simultaneous connections are present # netstat -auntpl | grep 192.168.0.24 | grep 22 | wc -l Part of active connections # netstat -auntpl | egrep -i "active|proto|192.168.0.24" | head -20 Nmap ..
Before making any changes in route always have backup of existing route tables and output. Its always good to proceed it with change, be cautious when you change or add routes. Get route table information # ip route show # ip route show table bond0 # ip route show table main ..
how to find defunt process on linuxbox Find and kill all defunct process in linux To find all defunct process # ps axo ppid,pid,stat,comm | grep -w defunct -w, --word-regexp Select only those lines containing matches that form whole words. The test is ..