Shell function lib for system config and deployment tasks, produces easy to read configs

deployer.sh

# Deployment shell functions
# 
# Several functions for creating users and groups, adding system
#+packages, and setting system parameters and security limits.
#
_LIBDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"

# create unix group, check if exists before
# params: name, id
create_group() {
  grep $1 /etc/group &> /dev/null
  [[ $? -eq 0 ]] || echo "groupadd -g $2 $1"
}

# create unix users, check if exists before
# params: name, id
create_user() {
  grep $1 /etc/passwd &> /dev/null
  [[ $? -eq 0 ]] || echo "useradd -u $2 -g $3 -G $4 $1"
}

# add sudoer file for user, all permissions, no pasword
# params: username
sudo_for() {
  _sudoer=/etc/sudoers.d/$1
  if [ ! -a ${_sudoer} ]
  then
    echo "echo \"$1  ALL=(ALL)  NOPASSWD: ALL\" > ${_sudoer}"
    echo "chmod 440 ${_sudoer}"
  fi
}

# create directory and chown to user:group
# params: directory, user:group
dir_for() {
  if [ ! -a $1 ]
  then
    echo "mkdir -p $1; chown -R $2 $1"
  fi
}

# setting system setting to value
# params: setting, value
set_sysctl() {
  _sysctl=/etc/sysctl.conf
  if grep -q $1 ${_sysctl}
  then
    echo "sed -i -e \"/$1/d\" ${_sysctl}"
  fi
  echo "echo \"$1=$2\" >> ${_sysctl}"
}

# activate the sysctl changes
# no params
activate_sysctl() {
  echo "/sbin/sysctl -p"
}

# setting system security limits
# params: setting, value
# TODO: check to create file in /etc/security/limits.d/.
set_limit() {
  _syslmt=/etc/security/limits.conf
  echo "echo \"$1\" >> ${_syslmt}"
}

# install packages
add_packages() {
  _packs=$1
  echo yum check-update
  eval echo yum install -y \${$_packs[*]}
}

# add repo epel for additional packages
add_epel_rpm() {
  echo "rpm -Uvh $1"
}

# disable system service via chkconfig
# param: service_name
disable_service() {
  chkconfig | grep $1 &> /dev/null
  [[ $? -eq 0 ]] && echo "chkconfig --del $1"
}