Question

I hope one of you bash, sed, awk experts out there can help me out. I have this string:

 00:00:00:00:00:00%~%System1%~%s0:00-21:40%~%m3:10-17:10%~%t11:20-20:30%~%w05:10-9:30%~%t00:00-21:30%~%f12:00-0:00%~%s6:00-18:00     

It is fields separated by “%~%”. The first two fields can be ignored. The remaining fields have day time ranges. This should clarify the format:

00:00:00:00:00:00 <--Mac
System1           <--Name
s00:00-21:40      <--Sunday 12 AM through 9:40 PM  
m03:10-17:10      <--Monday 3:10 AM through 5:10 PM
t11:20-20:30      <--Tuesday 11:20 AM through 8:30 PM
w05:10-9:30       <--Wednesday 5:10 AM through 9:30 AM
t00:00-21:30      <--Thursday 12 AM through 9:30 PM
f12:00-0:00       <--Friday 12 PM through 12:00 AM
s06:00-18:00      <--Saturday 6 AM through 6:00 PM

Now the trick…I need to determine if the current system datetime is within the ranges. 🙁

So, if date returns this:

 Wed Sep 19 14:26:05 UTC 2012

Then it doesn’t fall within the range specified for Wednesday. I basically need an if statement. I need to execute one script if it is within the range and a different script if it is not. How would I do that with bash, awk, and/or sed?

Thanks for any help you can offer!

I started going down this path:

arr=$(echo $line | tr "%~% " "\n")
for x in $arr
do
    #Now what?  Some kind of switch/case?
done

Answer 1

I believe that the following script does what you want:

#!/bin/bash

# Function which returns true (0) on a time being in a range, false (1) otherwise
# call as: time_between $time $range
# where $range is of the format 'START-END'
time_between() {
    current_time=$1
    range=$2

    start_time=$(echo $range | cut -d'-' -f1);
    end_time=$(echo $range | cut -d'-' -f2);

    # Correct if ends at midnight
    if [[ $end_time -eq 0 ]]; then
        let end_time=2400
    fi

    # Test is time is within the window
    if [[ $current_time -ge $start_time && $current_time -le $end_time ]]
    then
         return 0;
    fi

    # Else the time is outside the window
    return 1;
}

# Set the line variable - you may want this to come from somewhere else in the end  
line="00:00:00:00:00:00%~%System1%~%s0:00-21:40%~%m3:10-17:10%~%t11:20-20:30%~%w05:10-9:30%~%t00:00-21:30%~%f12:00-0:00%~%s6:00-18:00"

i=0

# Extract the day and time (hours and minutes) from the `date` command
DATE=$(date)
day=$(echo $DATE | cut -d' ' -f1)

time=$(echo $DATE | cut -d' ' -f4 | cut -d: -f1-2 | tr -d ':')

# Marker for which token in the line to start the days from: token 3 is monday
dayno=2

# Set the dayno so we're pointing at the current day
case $day in
Mon)
    let dayno+=1
;;
Tue)
    let dayno+=2
;;
Wed)
    let dayno+=3
;;
Thu)
    let dayno+=4
;;
Fri)
    let dayno+=5
;;
Sat)
    let dayno+=6
;;
Sun)
    let dayno+=7
;;
esac

arr=$(echo $line | tr '%~%' '\n' | tr -d '[a-z]:')

for x in $arr
do
    let i+=1;
    #Now what?  Some kind of switch/case?
    if [[ $i -eq $dayno ]]; then
        if time_between $time $x; then
            echo "Were within the window!"
        else
            echo "We missed the window!"
        fi
    fi
done