This shell script check the availability of web sites probing them with curl. With HTTP status code >= 400 the site is considered unavailable (and the script return 1). The script check also response time without affect script status code. On terminal the output is colored instead on redirect (for example when log script results into file) the o…

sites_check.sh

#!/bin/bash

# sites to check
site=(
  "www.google.com"
  "www.github.com"
  # insert here other sites...
)

# color costants
GREEN='\e[1;32m'
RED='\e[1;31m'
DARKCYAN='\e[0;36m'
CYAN='\e[1;36m'
RESET='\e[00m'

# counters
SITES_DOWN=0
SITES_SLOW=0

# do not print colors if we are redirecting output
COLOR(){
  if [ -t 1 ] ; then
    echo -ne $1
  fi
}

# total of sites
LEN=${#site[@]}

echo "Checking $LEN sites..."
echo

for element in $(seq 0 $(($LEN - 1)))
  do

  # do not print this if we are redirecting output
  if [ -t 1 ] ; then
    echo -ne "${DARKCYAN}Probing ${CYAN}${site[$element]}${DARKCYAN}...${RESET}"
  fi

  # run curl
  RET=`curl -sL -w "%{http_code} %{time_total}\\n" "${site[$element]}" -o /dev/null`
  HTTP_CODE=`echo $RET | cut -d' ' -f1`
  TIME=`echo $RET | cut -d' ' -f2`

  # put cursor at 1st column
  echo -en "\033[1G";

  if [ "$HTTP_CODE" -lt "400" ]; then
    # site up :)
    COLOR $GREEN
  else
    # site down :(
    SITES_DOWN=`expr $SITES_DOWN + 1`
    COLOR $RED
  fi

  # print HTTP status code
  echo -en $HTTP_CODE
  COLOR $RESET
  # print site name
  echo -en " "${site[$element]}

  # check if time is < 5 seconds
  if [ "`echo $TIME | cut -d',' -f1`" -gt "5" ]
  then
    # site very slow (> 5s)
    COLOR "\e[1;33m"
    SITES_SLOW=`expr $SITES_SLOW + 1`
  elif [ "`echo $TIME | cut -d',' -f1`" -gt "0" ]
  then
    # site slow (1 < time < 5)
    COLOR "\e[0;33m"
  else
    # site ok (< 1s)
    COLOR "\e[0;34m"
  fi

  # print time
  echo -en " [${TIME}s]"
  COLOR $RESET
  echo

done

# summary
echo
COLOR $DARKCYAN
echo -n "Sites probed: "
COLOR $CYAN
echo -n $LEN
COLOR $RESET

# sites down summary
if [ $SITES_DOWN -gt 0 ]; then
  COLOR $DARKCYAN
  echo -n ", "
  COLOR $RED
  echo -n $SITES_DOWN
  COLOR $DARKCYAN
  echo -n " down"
fi

# sites slow summery
if [ $SITES_SLOW -gt 0 ]; then
  COLOR $DARKCYAN
  echo -n ", "
  COLOR '\e[1;33m'
  echo -n $SITES_SLOW
  COLOR $DARKCYAN
  echo -n " slow"
fi

echo

if [ $SITES_DOWN -gt 0 ]; then
  # bonus: send desktop notification
  # DISPLAY=:0 notify-send -i dialog-error "Site check" "${SITES_DOWN} site(s) are not available"
  exit 1
else
  exit 0
fi