Shell script to keep system clean

cron_clean.sh

    #!/bin/bash
     
    OLDCONF=$(dpkg -l|grep "^rc"|awk '{print $2}')
    CURKERNEL=$(uname -r|sed 's/-*[a-z]//g'|sed 's/-386//g')
    LINUXPKG="linux-(image|headers|ubuntu-modules|restricted-modules)"
    METALINUXPKG="linux-(image|headers|restricted-modules)-(generic|i386|server|common|rt|xen)"
    OLDKERNELS=$(dpkg -l|awk '{print $2}'|grep -E $LINUXPKG |grep -vE $METALINUXPKG|grep -v $CURKERNEL)
    YELLOW="\033[1;33m"
    RED="\033[0;31m"
    ENDCOLOR="\033[0m"
     
    if [ $USER != root ]; then
      echo -e $RED"Error: must be root"
      echo -e $YELLOW"Exiting..."$ENDCOLOR
      exit 0
    fi
     
    echo -e $YELLOW"Cleaning apt cache..."$ENDCOLOR
    aptitude clean
     
    echo -e $YELLOW"Removing old config files..."$ENDCOLOR
    sudo aptitude purge $OLDCONF
     
    echo -e $YELLOW"Removing old kernels..."$ENDCOLOR
    sudo aptitude purge $OLDKERNELS
     
    echo -e $YELLOW"Emptying every trashes..."$ENDCOLOR
    rm -rf /home/*/.local/share/Trash/*/** &> /dev/null
    rm -rf /root/.local/share/Trash/*/** &> /dev/null
     
    echo -e $YELLOW"Script Finished!"$ENDCOLOR