Package mgmt
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dpkg
# dkpg does not install dependencies automatically # See if apache2 is installed dpkg -l | grep apache2 # List all files installed for ufw dpkg -L ufw # Which package installed a file dpkg -S /etc/host.conf # Install a local .deb file sudo dpkg -i zip_3.0-4_i386.deb # Uninstalling a package sudo dpkg -r zip -
apt - Ubuntu’s Advanced Packaging Tool (APT)
# apt [install | remove | update | upgrade] [$pkg1 $pkg2 ..] # Update the Package Index: The APT package index is essentially a database of available packages from the repositories defined in the /etc/apt/sources.list file and in the /etc/apt/sources.list.d directory. To update the index: apt update # discover to which package a file belongs apt-file search docker # Or using dpkg to find package names dpkg -S stdio.h # More apt help # Most used commands: list - list packages based on package names, [installed | upgradable ..] search - search in package descriptions = apt-cache search show - show package details = apt-cache show install - install packages remove - remove packages autoremove - Remove automatically all unused packages update - update list of available packages upgrade - upgrade the system by installing/upgrading packages full-upgrade - upgrade the system by removing/installing/upgrading packages edit-sources - edit the source information file # Diff between apt and apt-get: https://askubuntu.com/questions/445384/what-is-the-difference-between-apt-and-apt-get # apt is higher level of apt-get which is low level, backend of apt, and backwards compatible. apt is better for end-users and doesn't require or contain some extra features in that are present in apt-get.
Kernel Crash Dump
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sudo apt install linux-crashdump
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/etc/default/kdump-tools // USE_KDUMP=1
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Remote dump: SSH=“ubuntu@kdump-netcrash” or NFS=“kdump-netcrash:/var/crash” in /etc/default/kdump-tools
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Verification
cat /proc/cmdline // crashkernel boot parameter should be represented in /proc/cmdline -
Verify that the kernel has reserved the requested memory area for the kdump kernel
dmesg | grep -i crash kdump-config show -
Testing the Crash Dump Mechanism
cat /proc/sys/kernel/sysrq // SysRQ should be 1, if not, sudo sysctl -w kernel.sysrq=1 echo c > /proc/sysrq-trigger // to trigger the dump ls /var/crash