get status of last modification time of a file in linux

Question

I am trying to get the status whether the file is modified or not in Linux. I am using this piece of code and it works well, but it has a problem that it exit after the first "if" statement.

It does not look for elif statement. I am trying to get "warning" if the file is not modified from the last 2 minutes, and it should give me "critical" if it still does not modified for 4 minutes. it always show warning or OK but does not take into account the elif statement. the code i am using

#!/bin/bash
# How to execute ./sensor.sh tem_sensor
HOUR=$(date +%H)
MIN=$(date +%M)

# Directory where they are sensor directorys
DIR=/home/robbin/Desktop/sensor_collection/
# Name of selected sensor
SENSOR=$1
# Name of sensor's directoris
SENSORS=(sensor1)

# Loop in every folder
for i in ${SENSORS[@]}
do
        # We only want the specified sensor so we will skip until we found it
        if [[ $SENSOR != $i ]]; then continue ; fi
        # You take the hour and minute value from last file
        LHOUR=$(ls -lrt $DIR/$i| tail -n1 | awk '{ print $8}' | awk -F ':' '{ print $1}')
        LMIN=$(ls -lrt $DIR/$i | tail -n1 | awk '{ print $8}' | awk -F ':' '{ print $2}')
        # We calculate the diferences
        let FHOUR=$(( HOUR - LHOUR ))
        let FMIN=$(( MIN - LMIN ))

        # if the diference is greater than 2
        if ([ $FMIN -gt 02 ] && [ $FMIN -lt 04 ]); then
            echo "WARNING - More than 2 minutes without recieving data"
            exit 1 # We put warning!
        # Else if it is not more than 2
        # We check if we have an hour of diference!
        elif [[ $FMIN -gt 04 ]]; then
            echo "CRITICAL - More than 4 minutes without recieving data"
            exit 2 # We put Red alert!
        else
            echo "OK - We recieve data"
            exit 0 # Green alert if we dont have problems
        fi
done
echo "UNKNOW - Sensor not found"
exit 3

If someone help me to solve this problem. cox it seems that it has no problem and it should work expectedly. I am new to bash scripts. I would be grateful. .

Answer 1

You can re-arrange your if-else statements as follows:

if [[ $FMIN -gt 04 ]]; then
    echo "CRITICAL - More than 4 minutes without recieving data"
    exit 2 # We put Red alert!
elif [[ $FMIN -gt 02 ]]; then
    echo "WARNING - More than 2 minutes without recieving data"
    exit 1 # We put warning!
else
    echo "OK - We recieve data"
    exit 0 # Green alert if we dont have problems
fi

This is simpler to read and should do what you want.

Answer 2

You need to swap the conditions in the if and elif clauses. The first condition matches both cases, so the second one is never getting checked.