Linux Kernel

#
# configure parameter
#
# determine the maximum size of a shared memory segment
cat /proc/sys/kernel/shmmax
 
# set default shared memory limit for shmmax (16 GB)
echo 17179869184 > /proc/sys/kernel/shmmax
 
# add the following line to /etc/sysctl.conf to make a change permanent
echo "kernel.shmmax=4294967296" >> /etc/sysctl.d/90-shmmax.conf
 
# load parameter
/sbin/sysctl -p /etc/sysctl.d/90-shmmax.conf

XEN: Create Debian Jessie DomU VM

wget https://raw.githubusercontent.com/panticz/xen/master/domains/debian.jessie.sh -O - | bash -

#!/bin/bash

# configure domU
DOMAIN_NAME=jessie
DOMAIN_MAC=00:10:01:aa:bb:cc
DOMAIN_RAM=2Gb
DOMAIN_HDD=8Gb
 
# create domU on LVM (for image file use --dir=/root)
xen-create-image \
 --hostname=${DOMAIN_NAME} \
 --dist=jessie \
 --lvm=vg0 \
 --size=${DOMAIN_HDD} \
 --fs=ext4 \
 --role=udev \
 --memory=${DOMAIN_RAM} \
 --swap=${DOMAIN_RAM} \
 --dhcp \
 --mac=${DOMAIN_MAC} \
 --genpass=0 \
 --password=t00r \
 --vcpus $(cat /proc/cpuinfo | grep processor | wc -l) \
 --pygrub
 
# --apt_proxy=http://apt-cacher:3142/
 
# rename vm config
mv /etc/xen/${DOMAIN_NAME}.cfg /etc/xen/${DOMAIN_NAME}
 
# OPTIONAL: add to autostart
ln -s /etc/xen/${DOMAIN_NAME} /etc/xen/auto
 
# start domU
xm create -c ${DOMAIN_NAME}

# login
user: root
password: t00r

# disable pc speaker
echo 'blacklist snd-pcsp' >> /etc/modprobe.d/blacklist.conf

# fix FQDN
echo "$(ifconfig eth0| grep "inet addr" | cut -d ":" -f2 | cut -d" " -f1)     $(hostname).$(cat /etc/resolv.conf | grep domain | cut -d" " -f2) $(hostname)" >> /etc/hosts
 
# OPTIONAL: enable APT auto update
wget -q --no-check-certificate https://raw.githubusercontent.com/panticz/scripts/master/enable_auto_update.sh -O - | bash -

LXC: create Debian Jessie container

wget -q --no-check-certificate https://raw.githubusercontent.com/panticz/lxc/master/create.jessie.sh -O - | bash -s

#!/bin/bash

[ -z ${CONTAINER} ] && CONTAINER=jessie
LANG=en_US.UTF-8

# force, remove previous container
if [ "$1" == "-f" ]; then
  [ $(sudo lxc-ls ${CONTAINER} | wc -l) -gt 0 ] && sudo lxc-destroy -f -n ${CONTAINER}
  shift
fi

# create container
sudo lxc-create -t debian -n ${CONTAINER} -- template-options -r jessie $@

# workaround for "Failed to mount cgroup at /sys/fs/cgroup/systemd: Permission denied"
echo "lxc.aa_profile = unconfined" | sudo tee -a /var/lib/lxc/${CONTAINER}/config

# start container in background
sudo lxc-start -d -n ${CONTAINER}

# wait 3 seconds until network is up
sleep 3

# copy APT proxy configuration from host
APT_PROXY=$(grep -h "Acquire::http::Proxy" /etc/apt/* -r | head -1)
[ -n "${APT_PROXY}" ] && echo ${APT_PROXY} | sudo tee /var/lib/lxc/${CONTAINER}/rootfs/etc/apt/apt.conf.d/01proxy

# update packages in container
sudo lxc-attach -n ${CONTAINER} -- apt-get update
sudo lxc-attach -n ${CONTAINER} -- apt-get dist-upgrade -y

# show containers status
sudo lxc-ls ${CONTAINER} -f

(re)create container
wget -q --no-check-certificate https://raw.githubusercontent.com/panticz/lxc/master/create.jessie.sh -O - | bash -s -- -f

Allow root SSH login with password
CONTAINER=jessie
sudo lxc-attach -n ${CONTAINER} -- sed -i 's|PermitRootLogin without-password|PermitRootLogin yes|' /etc/ssh/sshd_config
sudo lxc-attach -n ${CONTAINER} -- service ssh restart

Fix DNS
echo nameserver 8.8.8.8 | sudo tee /var/lib/lxc/${CONTAINER}/rootfs/etc/resolv.conf

Default login credentials
user: root
pass: root

FixMe
"Failed to mount cgroup at /sys/fs/cgroup/systemd: Permission denied"
https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1346734

Failed to open /dev/autofs: No such file or directory
Failed to initialize automounter: No such file or directory
[FAILED] Failed to set up automount Arbitrary Executable File Formats File System Automount Point.
See 'systemctl status proc-sys-fs-binfmt_misc.automount' for details.
Unit proc-sys-fs-binfmt_misc.automount entered failed state.

Socket service systemd-udevd.service not loaded, refusing.
[FAILED] Failed to listen on udev Kernel Socket.
See 'systemctl status systemd-udevd-kernel.socket' for details.
Socket service systemd-udevd.service not loaded, refusing.
[FAILED] Failed to listen on udev Control Socket.
See 'systemctl status systemd-udevd-control.socket' for details.

Bugs
https://bugs.launchpad.net/ubuntu/+source/lxc/+bug/1347020
https://wiki.debian.org/LXC#Incompatibility_with_systemd

Fix DNS
echo nameserver 8.8.8.8 > /var/lib/lxc/${CONTAINER}/rootfs/etc/resolv.conf

# test
http://without-systemd.org/wiki/index.php/How_to_remove_systemd_from_a_Debian_jessie/sid_installation

Debian Jessie

wget -q --no-check-certificate https://raw.githubusercontent.com/panticz/lxc/master/create.jessie.sh -O - | bash -

#!/bin/bash

[ -z ${CONTAINER} ] && CONTAINER=jessie
LANG=en_US.UTF-8

# force, remove previous container
if [ "$1" == "-f" ]; then
  [ $(sudo lxc-ls ${CONTAINER} | wc -l) -gt 0 ] && sudo lxc-destroy -f -n ${CONTAINER}
  shift
fi

# create container
sudo lxc-create -t debian -n ${CONTAINER} -- template-options -r jessie $@

# workaround for "Failed to mount cgroup at /sys/fs/cgroup/systemd: Permission denied"
echo "lxc.aa_profile = unconfined" | sudo tee -a /var/lib/lxc/${CONTAINER}/config

# start container in background
sudo lxc-start -d -n ${CONTAINER}

# wait 3 seconds until network is up
sleep 3

# copy APT proxy configuration from host
APT_PROXY=$(grep -h "Acquire::http::Proxy" /etc/apt/* -r | head -1)
[ -n "${APT_PROXY}" ] && echo ${APT_PROXY} | sudo tee /var/lib/lxc/${CONTAINER}/rootfs/etc/apt/apt.conf.d/01proxy

# update packages in container
sudo lxc-attach -n ${CONTAINER} -- apt-get update
sudo lxc-attach -n ${CONTAINER} -- apt-get dist-upgrade -y

# show containers status
sudo lxc-ls ${CONTAINER} -f

LXC: create Debian Wheezy container

wget -q --no-check-certificate https://raw.githubusercontent.com/panticz/lxc/master/create.wheezy.sh -O - | bash -

#!/bin/bash

[ -z ${CONTAINER} ] && CONTAINER=wheezy
LANG=en_US.UTF-8

# force, remove previous container
if [ "$1" == "-f" ]; then
  [ $(sudo lxc-ls ${CONTAINER} | wc -l) -gt 0 ] && sudo lxc-destroy -f -n ${CONTAINER}
  shift
fi

# create container
sudo lxc-create -t debian -n ${CONTAINER} -- template-options -r wheezy $@

# set container MAC address if specified
if [ ! -z ${CONTAINER_MAC} ]; then
  sed -i "s|lxc.network.hwaddr = .*|lxc.network.hwaddr = ${CONTAINER_MAC}|" /var/lib/lxc/${CONTAINER}/config
fi

# start container in background
sudo lxc-start -d -n ${CONTAINER}

# wait 3 seconds until network is up
sleep 3

# copy APT proxy configuration from host
APT_PROXY=$(grep -h "Acquire::http::Proxy" /etc/apt/* -r | head -1)
[ -n "${APT_PROXY}" ] && echo ${APT_PROXY} | sudo tee /var/lib/lxc/${CONTAINER}/rootfs/etc/apt/apt.conf.d/01proxy

# update packages in container
sudo lxc-attach -n ${CONTAINER} -- apt-get update
sudo lxc-attach -n ${CONTAINER} -- apt-get dist-upgrade -y

# show containers status
sudo lxc-ls ${CONTAINER} -f

(re)create container
wget -q --no-check-certificate https://raw.githubusercontent.com/panticz/lxc/master/create.wheezy.sh -O - | bash -s -- -f

Default login credentials
user: root
pass: root

Fix DNS
echo nameserver 8.8.8.8 > /var/lib/lxc/${CONTAINER}/rootfs/etc/resolv.conf

LXC: create Debian Squeeze container

wget -q --no-check-certificate https://raw.githubusercontent.com/panticz/lxc/master/create.squeeze.sh -O - | bash -

#!/bin/bash

[ -z ${CONTAINER} ] && CONTAINER=squeeze
LANG=en_US.UTF-8

# force, remove previous container
if [ "$1" == "-f" ]; then
  [ $(sudo lxc-ls ${CONTAINER} | wc -l) -gt 0 ] && sudo lxc-destroy -f -n ${CONTAINER}
  shift
fi

# create container
sudo lxc-create -t debian -n ${CONTAINER} -- template-options -r squeeze $@

# start container in background
sudo lxc-start -d -n ${CONTAINER}

# wait 3 seconds until network is up
sleep 3

# copy APT proxy configuration from host
APT_PROXY=$(grep -h "Acquire::http::Proxy" /etc/apt/* -r | head -1)
[ -n "${APT_PROXY}" ] && echo ${APT_PROXY} | sudo tee /var/lib/lxc/${CONTAINER}/rootfs/etc/apt/apt.conf.d/01proxy

# update packages in container
sudo lxc-attach -n ${CONTAINER} -- apt-get update
sudo lxc-attach -n ${CONTAINER} -- apt-get dist-upgrade -y

# show containers status
sudo lxc-ls ${CONTAINER} -f

(re)create container
wget -q --no-check-certificate https://raw.githubusercontent.com/panticz/lxc/master/create.squeeze.sh -O - | bash -s -- -f

Default login credentials
user: root
pass: root

Fix DNS
echo nameserver 8.8.8.8 > /var/lib/lxc/${CONTAINER}/rootfs/etc/resolv.conf

Ubuntu: Ericsson H5321gw / F5521gw mini PCI-e WWAN / UMTS card

Ericsson H5321gw (Thinkpad T530)
# lsusb | grep Ericsson
Bus 003 Device 004: ID 0bdb:1926 Ericsson Business Mobile Networks BV

# fix kernel driver
echo "/etc/modprobe.d/avoid-mbib.conf" > options cdc_ncm prefer_mbim=N

cat < /etc/udev/rules.d/99-mbm.rules
ATTRS{idVendor}=="0bdb", ATTRS{idProduct}=="1926",
ENV{ID_USB_INTERFACE_NUM}=="09", ENV{MBM_CAPABILITY}="gps_nmea"
ATTRS{idVendor}=="0bdb", ATTRS{idProduct}=="1926",
ENV{ID_USB_INTERFACE_NUM}=="03", ENV{MBM_CAPABILITY}="gps_ctrl"
EOF

# force USB modem to only connect via EDGE and not 3G?

Git

git hooks post-merge example

#!/bin/bash

# check for modified files
for FILE in $(git diff-tree -r --name-only --no-commit-id ORIG_HEAD HEAD); do
  case "${FILE}" in
    *.json)
      # Repository configuration changed: update configuration
      ~/my_repository/scripts/json_update.sh
      ;;
    cronjobs/crontab)
      # Crontab changed: update user cronjobs
      ~/my_repository/scripts/crontab_update.sh
      ;;
  esac
done

# show repository info
git config -l

# show diff for one file
git diff

# commit only one file
git commit -m 'my comment' path/to/file

# create Git repository
git init

# add all files
git add .

# commit
git commit -m "initial project version"

# list tag
git tag -l

checkout
# checkout over SSH
git clone git@github.com:foo/bar.git

# pull single file
git checkout filename

# pull single file from remote
git checkout origin/master -- path/to/file

# checkout to checkout to specific folder
git clone https://github.com/panticz/installit.git /path/to/folder

# checkout tag
git checkout 1.0.2

# git pull single file
git checkout origin/master -- file_name

# rollback to revision
git checkout 96fe40ded8277725d244aac83c42256ad554cc3b .

# switch branch
git checkout branch_name
git checkout master

# checkout branch
git clone --branch --single-branch []

# test
git reset file/to/overwrite

# search for string
git grep "string/regexp" $(git rev-list --all)

# grep
git grep foo HEAD

# remove last commit
git reset HEAD~1

# reset to latest revision
git reset --hard

git cherry-pick commit1

branch
# diff between branches
git diff master

# show branches
git branch

# push local Git branch to remote master branch
git push origin local_branch_1:master

# delete local branch
git branch -d local_branch_name

# delete remote branch
git push origin :remote_branch_name

# ignore
./.gitignore

# git global setup
git config --global user.name "first_name last_name"
git config --global user.email "user@example.com"

# create a new repository
git clone git@example.com:repository_group/repository_name.git
cd repository_name
touch README.md
git add README.md
git commit -m "add README"
git push -u origin master

# Add existing folder or Git repository
cd existing_folder
git init
git remote add origin git@example.com:repository_group/repository_name.git
git add .
git commit
git push -u origin master

Debian: Compile and install multiple PHP CLI versions

# install dependencies
apt-get install -y build-essential
 
# download and compile PHP
for VERSION in 5.3.29 5.4.38 5.5.22 5.6.6; do
    wget -q "http://de1.php.net/get/php-${VERSION}.tar.bz2/from/this/mirror" -O- | tar xj -C /tmp
    cd /tmp/php-${VERSION}
    ./configure --prefix=/opt/php/${VERSION%.*} --disable-all --disable-cgi
    make install -j5
done
 
# add to PATH
for i in /opt/php/*; do
    ln -s $i/bin/php /usr/local/bin/php${i##*/}
done
 
# create backup
cd /opt/php
tar -cjf /tmp/opt.php.$(date -I).tar.bz2 *
 
# test backup
tar -tvf /tmp/opt.php.$(date -I).tar.bz2

Create a restricted user for SSH tunneling

wget -q --no-check-certificate https://raw.githubusercontent.com/panticz/scripts/master/create_ssh_tunnel_user.sh -O - | bash -

#!/bin/bash

# create new restricted user
useradd tunnel --gid nogroup --create-home --skel /dev/null --shell /bin/rbash

# set random encrypted password to enable login
echo "tunnel:$(openssl rand -base64 32)" | chpasswd

# create authorized_keys
mkdir /home/tunnel/.ssh
chmod 700 /home/tunnel/.ssh
touch /home/tunnel/.ssh/authorized_keys
chmod 600 /home/tunnel/.ssh/authorized_keys

# remove path to programs
echo 'PATH=' > /home/tunnel/.profile
chmod 400 /home/tunnel/.profile

# restrict permissions
chmod 500 /home/tunnel
chown tunnel:nogroup /home/tunnel -R

Add your public key(s)
cat /tmp/authorized_keys > /home/tunnel/.ssh/authorized_keys
sed -i 's|ssh-rsa|command="/bin/false",no-pty,no-X11-forwarding ssh-rsa|g' /home/tunnel/.ssh/authorized_keys

# parameter
command="/bin/false",no-agent-forwarding,no-pty,no-user-rc,no-X11-forwarding,permitopen="127.0.0.1:80"
no-pty,no-port-forwarding,no-X11-forwarding,no-agent-forwarding

Links
http://www.gnu.org/software/bash/manual/html_node/The-Restricted-Shell.html

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