Using diff to create a patch in Linux
Create the patch: diff -aru file.orig file > file.patch Apply the patch (-b creates a copy of the original with a .orig extension): patch -b file file.patch
Tags Archives linux
Using badblocks to test and wipe disks
Non destructive (read only) test, optimized for 1G RAM: badblocks -b 4096 -c 98304 -p 0 -s /dev/sda Destructive read/write test (use caution!): badblocks -b 4096 -c 98304 -p 0 -w -s /dev/sda
Mcelog – Bad memory?
The original hardware did all kinds of strange things, stuff like SSH not working and RPM checksums failing, random rebooting, ect. I ended up swapping the chassis, mainboard and RAM but kept the HDD’s to avoid an OS reinstall. Now, I’ve gotten this twice on the new box followed by a hard freeze about 2 […]
Cpanel: Force backup run
When setting up a new server or finishing a migration, it’s a good idea to force a backup run: /scripts/cpbackup –force
Write speed on Linux
A quick non-destructive test of disk write performance on Linux. Useful for testing cheap HDD’s (write will almost always be worse than read): dd if=/dev/zero of=test bs=64k count=16k conv=fdatasync
Vanilla Kernel on CentOS
If compiling a Vanilla kernel for CentOS, you may encounter the following after rebooting: Setuproot: moving /dev failed: No such file or directory Setuproot: error mounting /proc: No such file or directory Setuproot: error mounting /sys: No such file or directory […] Kernel panic – not syncing: Attempted to kill init! To resolve the booting […]
Copy one disk to another using Linux and DD
The following will copy two disks, partition table and all, with forensic quality, and pad the destination disk with zeroes if any data is unreadable on the source disk. Be sure you’ve identified which disk is which using combinations of dmesg and ‘fdisk -l’. The destination disk must also be equal or greater in size. […]
Linux: Shutdown/Poweroff command
The other day I was surprised to find the ‘shutdown -h now’ command on the Redhat/Centos rescue CD doesn’t work. I’ve since discovered a few other ways to get a Linux OS to power off, each should accomplish the same thing – gracefully power down. shutdown -h now halt poweroff init 0
Linux: Sort disk usage with awk
Sort the output of ‘du’ in human readable format (similar to the -h switch). du -k | sort -nr | awk ‘ BEGIN { split(“KB,MB,GB,TB”, Units, “,”); } { u = 1; while ($1 >= 1024) { $1 = $1 / 1024; u += 1 } $1 = sprintf(“%.1f %s”, $1, Units[u]); print $0; } […]
Fixing RTL8111/8168B kernel module on Debian/Ubuntu
For many years, issues with the r8169 module have plagued Debian and related Linux distributions such as Ubuntu. You’ll see lots of ifconfig errors and stuff like this on desktop mainboards with a Realtek NIC: Oct 29 07:40:32 c1100d335 kernel: [1996163.743022] NETDEV WATCHDOG: eth0: transmit timed out Oct 29 07:40:32 c1100d335 kernel: [1996163.777667] r8169: eth0: […]