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Commands tagged kernel from sorted by
Terminal - Commands tagged kernel - 32 results
apt purge linux*{14..18}*
2016-04-20 07:44:55
User: ppq
Functions: apt

If, for example, you want to remove all kernels and headers but the last three versions, you can't use one of that magic all-in-one "remove old stuff" commands.

With this simple but elegant command you can remove a range of versions, or a list of versions with e.g. {14,16,20}.

sudo apt-get purge $(dpkg -l linux-{image,headers}-"[0-9]*" | awk '/ii/{print $2}' | grep -ve "$(uname -r | sed -r 's/-[a-z]+//')")
sudo sh -c 'echo 1 > /proc/sys/kernel/dmesg_restrict'
2015-03-13 20:54:45
User: Blacksimon
Functions: sh sudo

Linux offers an interesting option to restrict the use of dmesg. It is available via /proc/sys/kernel/dmesg_restrict.

You can check the status with:

cat /proc/sys/kernel/dmesg_restrict

Alternatively you can use sysctl:

sudo sysctl -w kernel.dmesg_restrict=1

To make your change persistent across reboot, edit a fille in /etc/sysctl.d/.

sysctl --system
2015-01-29 07:56:36
User: tankywoo
Functions: sysctl

Use `sysctl -p` without argument will only load /etc/sysctl.conf, but user configs always put in /etc/sysctl.d/*.conf, `sysctl --system` will load all the config files

echo 1 > /proc/sys/sunrpc/nfs_debug
2014-08-12 14:40:55
User: harpo
Functions: echo

echo 1 > /proc/sys/sunrpc/nfs_debug && tail -f /var/log/messages

to debug NFS issues.

dpkg -l linux-* | awk '/^ii/{ print $2}' | grep -v -e `uname -r | cut -f1,2 -d"-"` | grep -e [0-9] | xargs sudo apt-get -y purge
curl -s -k https://www.kernel.org/feeds/kdist.xml | sed -n -e 's@.*<guid>\(.*\)</guid>.*@\[email protected]' | grep 'stable' | head -1 | awk -F , '{print $3}'
2013-12-17 23:59:27
User: Wafelijzer
Functions: awk grep head sed
Tags: kernel

Fetches latest stable release version from first entry between tags

echo c > /proc/sysrq-trigger
2013-05-07 19:41:40
User: fangfufu
Functions: echo
Tags: kernel

Well, this is quite useful for testing if your hardware watchdog is working properly.

lsmod | grep -io MODULENAME| xargs modinfo | grep -iw version
2013-03-18 07:52:14
User: adriano
Functions: grep lsmod modinfo xargs
Tags: kernel modules

Returns the version of the kernel module specified as "MODULENAME", when available.

/sbin/sysctl -p
2013-02-14 12:48:26
User: Risthel

Reload all defined kernel variables from /etc/sysctl.conf(if no parameter after -p is given) without the old myth "Ah, you'll need to reboot to apply those variables"...

uname -m # display machine "hardware name"
2013-01-04 11:46:43
User: mpb
Functions: uname

Display the machine "hardware name" 32 or 64 bit.

"x86_64" is shown on 64 bit machines

"i686" is typically shown on 32 bit machines (although, you might also see "i386" or "i586" on older Linuxen).

On other "unix-like" systems, other hardware names will be displayed.

For example, on AIX, "uname -m" gives the "machine sequence number".

For whatever reason, IBM decided that "uname -M" would give the machine type and model.

(ref: http://www.ibm.com/developerworks/aix/library/au-aix-systemid.html )

On Sun Solaris, "uname -m" can be used to determine the chip type and "isainfo -v" will reveal

if the kernel is 64 or 32 bit.

(ref: http://www.ibiblio.org/pub/packages/solaris/sparc/html/32.and.64.bit.packages.html )

A more reliable way to determine "64-bit ness" across different Unix type systems is to compile the following simple C program:

cat <<eeooff > bits.c


* program bits.c

* purpose Display "32" or "64" according to machine type

* written January 2013

* reference http://www.unix.org/whitepapers/64bit.html


/* hmm, curious that angle-brackets removed by commandlinefu.com data input processing? */

#include "/usr/include/stdio.h"

long lv = 0xFFFFFFFF;

main ( ) {

printf("%2d\n",(lv < 0)?32:64);



Compile and run thusly: cc -o bits bits.c; ./bits

isainfo -v
2013-01-04 03:07:28
User: halcyonblue

This is likely only valid on Solaris based systems. Unfortunately a lot of the more universal techniques for determining if a system is 32bit or 64bit on x86 solaris fail to give much more information than "i86pc"

getconf LONG_BIT
2012-12-12 23:51:51
User: varghjarta
Functions: getconf

Needed a quick way to see if my server distro that I setup years ago was running 32bit or not, since with time I had forgotten.

Note: does not check _hardware_ e.g. /proc/cpuinfo but rather the kernel installed

modprobe --show-depends module_name
2012-08-17 16:54:52
User: miguelcnf
Functions: modprobe

Use modprobe to list all the dependencies of a certain kernel module. Handy when debugging system issues.

sudo apt-get remove $(dpkg -l|awk '/^ii linux-image-/{print $2}'|sed 's/linux-image-//'|awk -v v=`uname -r` 'v>$0'|sed 's/-generic*//'|awk '{printf("linux-headers-%s\nlinux-headers-%s-generic*\nlinux-image-%s-generic*\n",$0,$0,$0)}')
2012-08-15 10:02:12
User: mtron
Functions: awk sed sudo

Remove old kernels (*-generic and *-generic-pae) via apt-get on debian/ubuntu based systems. Tested on ubuntu 10.04 - 12.04.

curl 'https://www.kernel.org/kdist/finger_banner'
2012-03-04 21:10:19
User: Testuser_01

Gets the (previously obtainable with:

finger @kernel.org

) info of the latest linux kernel versions available.

sudo dpkg -i `ls -tr *.deb | tail -n4`
2011-10-09 14:20:11
User: _john
Functions: sudo tail

after kernel build with make deb-pkg, I like to install the 4 newest packages that exist in the directory. Beware: might be fewer for you....

apt-get remove $(dpkg -l | awk "/^ii linux-(image|headers)/ && ! /`uname -r`/ {print \$2}")
2011-10-09 13:58:47
User: _john
Functions: apt awk

since awk was already there one can use it instead of the 2 greps. might not be faster, but fast enough

echo "root=/dev/sda7" > /proc/param.conf
2011-09-27 18:06:53
User: totti
Functions: echo

Then exit from the shell.


some time need to exit twice

exit exit

Now the OS will boot with the new parameters.

grep -2riP '\b(fuck|shit|bitch|tits|ass\b)' /usr/src/linux/
zgrep CONFIG_MAGIC_SYSRQ /proc/config.gz
sudo aptitude remove -P $(dpkg -l|awk '/^ii linux-image-2/{print $2}'|sed 's/linux-image-//'|awk -v v=`uname -r` 'v>$0'|sed 's/-generic//'|awk '{printf("linux-headers-%s\nlinux-headers-%s-generic\nlinux-image-%s-generic\n",$0,$0,$0)}')
2011-04-25 05:19:57
User: Bonster
Functions: awk sed sudo

Same as 7272 but that one was too dangerous

so i added -P to prompt users to continue or cancel

Note the double space: "...^ii␣␣linux-image-2..."

Like 5813, but fixes two bugs: [1]This leaves the meta-packages 'linux-headers-generic' and 'linux-image-generic' alone so that automatic upgrades work correctly in the future. [2]Kernels newer than the currently running one are left alone (this can happen if you didn't reboot after installing a new kernel).

aptitude remove $(dpkg -l|awk '/^ii linux-image-2/{print $2}'|sed 's/linux-image-//'|awk -v v=`uname -r` 'v>$0'|sed 's/-generic//'|awk '{printf("linux-headers-%s\nlinux-headers-%s-generic\nlinux-image-%s-generic\n",$0,$0,$0)}')
2010-12-11 11:38:15
User: __
Functions: awk sed

Note the double space: "...^ii␣␣linux-image-2..."

Like 5813, but fixes two bugs: [1]This leaves the meta-packages 'linux-headers-generic' and 'linux-image-generic' alone so that automatic upgrades work correctly in the future. [2]Kernels newer than the currently running one are left alone (this can happen if you didn't reboot after installing a new kernel).

I'm bummed that this took 228 characters. I'd like to see a simpler version.

echo 0 > /proc/sys/kernel/randomize_va_space
2010-07-11 16:42:42
User: gunslinger_
Functions: echo
Tags: kernel

Disable randomisation address