Bash 101 while loop fail

rbees · 02-12-2015, 02:40 PM

Ladies and Gents,

Still failing bash 101

I am a copy/paste person and don't really know how to write code. I only know what I want it to do. Most of the code below comes from other working scripts with a few small changes relevant to what I am trying to do. Since the code doesn't work my changes are a "fail".

What this code is suppose to do is take the input day and check to see if it is a Jewish Holiday. So the civil date needs to be converted to a Hebrew date. Hdate will do that and output the Hebrew Holiday, or a blank line.

For example

Code:

:~$ hdate -dhq 5 3 2015 

Thursday, 5 March 2015, 14 Adar 5775
Purim
:~$

So I need the 3rd line of the output, or at least I think it is the third line. That's where the data I need is if I redirect the output to a file. I am trying to test if that line has data or is blank. If blank, then loop to check the next day and so on for 7 days.

If there is data in that line then I am trying to compare it to a cvs data file with a listing of the Jewish Holidays to get other data so automated events (not implemented yet) can be scheduled for that day based on that data.

The Code:

Code:

#!/bin/bash

STORDIR="${HOME}/bin/shabbat/data"
set -x
DAY=5
MONTH=3
YEAR=2015

i=1
  while [ $i -lt 7 ]; do
    YOMTOVE=`echo "$(hdate -dhq $DAY $MONTH $YEAR)" | head -n 3 | tail -n +3 `
    echo "$YOMTOVE"
    if [[ "$YOMTOVE" != "" ]]; then  
      grep ^"$YOMTOVE" "$STORDIR"/YomTove.cvs
    i=$[$i+1]
    DAY=$[$DAY+1]
    fi
  done

When I run this my shell goes into a open ended loop with this type of output.

Code:

+ [[ '' != '' ]]
+ '[' 3 -lt 7 ']'
++ head -n 3
++ tail -n +3
+++ hdate -dhq 7 3 2015
++ echo '
Saturday, 7 March 2015, 16 Adar 5775'
+ YOMTOVE=
+ echo ''

+ [[ '' != '' ]]
+ '[' 3 -lt 7 ']'
++ head -n 3
++ tail -n +3
+++ hdate -dhq 7 3 2015
++ echo '
Saturday, 7 March 2015, 16 Adar 5775'
+ YOMTOVE=
+ echo ''

+ [[ '' != '' ]]

After a reboot the code checks the correct date (5 March 2015) the second time the code is run it checks an incorrect date (7 March 2015). No idea why. It also does not seem to be stepping through the while loop.

smallpond · 02-12-2015, 03:03 PM

Shalom,
Your problem is the way you are trying to pick out the 3rd record. A simpler way is to use awk to just print the 3rd line:

Code:

echo "$(hdate -dhq $DAY $MONTH $YEAR)" | awk 'NR == 3'

Also, your increment probably needs to be outside the if statement. Right now it only increments when YOMTOVE is not blank.

Code:

    if [[ "$YOMTOVE" != "" ]]; then  
        grep ^"$YOMTOVE" "$STORDIR"/YomTove.cvs
    fi
    i=$(( i + 1 ))

rbees · 02-12-2015, 03:32 PM

Thanks smallpond, Alechem Shalom

That did it.

What is the best way to make it step over a new month? Something like running a check on $DAY and if it is larger than 28 somehow test $MONTH to see when it will change. Guess I will have to think on it some.

grail · 02-12-2015, 09:23 PM

smallpond has helped with the issue, may I suggest some cosmetic changes which may also help in making things clearer

Code:

while [ $i -lt 7 ]; do
...
i=$[$i+1]
done

for (( i = 1; i < 7; i++)); do
...
done
##########
YOMTOVE=`echo "$(hdate -dhq $DAY $MONTH $YEAR)" | head -n 3 | tail -n +3 `

YOMTOVE=$(hdate -dhq $DAY $MONTH $YEAR | awk 'NR==3')
# only a modification to smallpond's suggestion
##########
if [[ "$YOMTOVE" != "" ]]; then

if [[ -n "$YOMTOVE" ]]; then
##########
DAY=$[$DAY+1]

(( DAY++ ))

rbees · 02-13-2015, 08:19 AM

Thanks grail

I like that, it looks cleaner too. On the plus side I actually understand what it does.

But now by trying to account for leap years I have made it not work again and I don't understand why. I am getting

Code:

:~$ bin/shabbat/test
bin/shabbat/test: line 90: syntax error near unexpected token `}'
bin/shabbat/test: line 90: `}'

My guess is that I am not following the logic through correctly and I have too many, or not enough "fi" in the right place.

The Current code

Code:

#!/bin/bash

STORDIR="${HOME}/bin/shabbat/data"
DAY=28
MONTH=1
YEAR=2016

# Calculate next day accounting for leap years
function Next_Day
{
  if [[ "$DAY" -le "27" ]]; then
    let i=i+1
    let DAY=DAY+1
    exit
    
  elif [[ "$DAY" = "28" ]]; then
    case ${ $MONTH } in
      1) 
      FULL="31"
      ;;
      2)
      FULL="28"
      ;;
      3)
      FULL="31"
      ;;
      4) 
      FULL="30"
      ;;
      5)
      FULL="31"
      ;;
      6)
      FULL="30"
      ;;
      7) 
      FULL="31"
      ;;
      8)
      FULL="31"
      ;;
      9)
      FULL="30"
      ;;
      10) 
      FULL="31"
      ;;
      11)
      FULL="30"
      ;;
      12)
      FULL="31"
      ;;
    esac

    if [[ $MONTH == "2" ]];then
      rem1=$((YEAR%4))
      rem2=$((YEAR%100))
      rem3=$((YEAR%400))

    if [ ${rem3} = "0" ];then
      $FULL="29"
      exit
      fi
  
    if [ ${rem2} = "0" -a ${rem3} != "0" ];then
      # echo "$YEAR Is Not A Leap Year"
      exit
      fi

    if [ ${rem1} = "0" -a ${rem2} != "0" ];then
      # echo "$YEAR Is A Leap Year"
      $FULL="29"
      else
      # echo "$YEAR Is Not A Leap Year"
      exit
    fi
  fi
      
  if [ ${DAY} = ${FULL} -a ${MONTH} -lt "12" ]; then
    let MONTH=MONTH+1
    let DAY=1
    exit

  elif [ ${DAY} = ${FULL} -a ${MONTH} = "12" ];then
    let YEAR=YEAR+1
    let MONTH=1
    let DAY=1
    exit  
  fi
}

################# 
# # Main Code # #
#################

for (( i = 1; i < 7; i++)); do
    
    YOMTOVE=$(hdate -dhq $DAY $MONTH $YEAR | awk 'NR==3')
    echo "$YOMTOVE"
    if [[ -n "$YOMTOVE" ]]; then
      grep ^"$YOMTOVE" "$STORDIR"/YomTove.cvs
      # actions based on what holiday it is
    fi
done
Next_Day

exit

rbees · 02-13-2015, 09:19 AM

I went through the logic for the 100th time and made some more changes and cleaned the code up a little but I am still getting the same thing.

Code:

#!/bin/bash

STORDIR="${HOME}/bin/shabbat/data"
DAY=28
MONTH=1
YEAR=2016

# Calculate next day accounting for leap years
function Next_Day
{
  case ${ $MONTH } in
      1) 
      FULL="31"
      ;;
      2)
      FULL="28"
      ;;
      3)
      FULL="31"
      ;;
      4) 
      FULL="30"
      ;;
      5)
      FULL="31"
      ;;
      6)
      FULL="30"
      ;;
      7) 
      FULL="31"
      ;;
      8)
      FULL="31"
      ;;
      9)
      FULL="30"
      ;;
      10) 
      FULL="31"
      ;;
      11)
      FULL="30"
      ;;
      12)
      FULL="31"
      ;;
  esac

  if [[ "$DAY" -le "27" ]]; then
    (( DAY++ ))
    exit
    
  elif [[ ${MONTH} == "2" ]]; then
      rem1=$((YEAR%4))
      rem2=$((YEAR%100))
      rem3=$((YEAR%400))

      if [ ${rem3} = "0" ]; then
	$FULL="29"
	exit
      fi
  
      if [ ${rem2} = "0" -a ${rem3} != "0" ]; then
	# echo "$YEAR Is Not A Leap Year"
	exit
      fi

      if [ ${rem1} = "0" -a ${rem2} != "0" ]; then
	# echo "$YEAR Is A Leap Year"
	$FULL="29"
      else
	# echo "$YEAR Is Not A Leap Year"
	exit
      fi
  
      if [ ${DAY} = ${FULL} -a ${MONTH} -lt "12" ]; then
	(( MONTH++ ))
	(( DAY++ ))
	exit
      fi

      elif [ ${DAY} = ${FULL} -a ${MONTH} = "12" ]; then
	(( YEAR++ ))
	let MONTH=1
	let DAY=1
	exit  
      fi
  exit
  fi
}

################# 
# # Main Code # #
#################

for (( i = 1; i < 7; i++)); do
    
    YOMTOVE=$(hdate -dhq $DAY $MONTH $YEAR | awk 'NR==3')
    echo "$YOMTOVE"
    if [[ -n "$YOMTOVE" ]]; then
      grep ^"$YOMTOVE" "$STORDIR"/YomTove.cvs
      # actions based on what holiday it is
    fi
done
Next_Day

exit

grail · 02-13-2015, 11:30 AM

Yes your if's are out of balance. Placing just the if's in vim and formatting it tells me that the last fi is not required, ie the one after exit.
However, I would guess that you have put an additional one in earlier, maybe before the last elif???

Also, you use the round brackets for the for loop and incrementing but then not for testing your values. Whenever working with numbers in bash, use your round brackets, eg.

Code:

elif [ ${DAY} = ${FULL} -a ${MONTH} = "12" ]; then

elif (( DAY == FULL && MONTH == 12 )); then

You can also use standard arithmetic symbols, such as <,>, <= and so on

rbees · 02-13-2015, 12:41 PM

Thanks,

You know I have looked that over 100 times and still didn't see that extra fi.

Quote:

Whenever working with numbers in bash, use your round brackets,

But it don't seem to work.

Code:

:~$ bin/shabbat/test
bin/shabbat/test: line 54: syntax error near unexpected token `then'
bin/shabbat/test: line 54: `  else (( MONTH == 2 )); then'
:~$ bin/shabbat/test
bin/shabbat/test: line 54: syntax error near unexpected token `then'
bin/shabbat/test: line 54: `  else (( MONTH = 2 )); then'

rbees · 02-13-2015, 01:34 PM

the current code

Code:

#!/bin/bash

STORDIR="${HOME}/bin/shabbat/data"
DAY=28
MONTH=1
YEAR=2016

# Calculate next day accounting for leap years
function Next_Day
{
  case $MONTH in [13578] | 1[02] ) FULL=31;;
    [469] | 1[01] ) FULL=30;;
    2) FULL=28;;
  esac

  if (( DAY <= 27 )); then
    (( DAY++ ))
    exit
    
  else (( MONTH = 2 )); then
      rem1=$((YEAR%4))
      rem2=$((YEAR%100))
      rem3=$((YEAR%400))

      if (( rem3 == 0 )); then
	FULL="29"
	exit
      fi
  
      if (( rem2 == 0 && rem3 != 0 )); then
	FULL="28"
	exit
      fi

      if (( rem1 == 0 && rem2 != 0 )); then
	FULL="29"
      else
	FULL="28"
	exit
      fi
  
      if (( DAY == FULL && MONTH < 12 )); then
	(( MONTH++ ))
	(( DAY++ ))
	exit

      elif (( DAY == FULL && MONTH == 12 )); then
	(( YEAR++ ))
	let MONTH=1
	let DAY=1
	exit  
      fi
  exit
  fi
}

################# 
# # Main Code # #
#################

for (( i = 1; i < 7; i++)); do
    
    YOMTOVE=$(hdate -dhq $DAY $MONTH $YEAR | awk 'NR==3')
    echo "$YOMTOVE"
    if [[ -n "$YOMTOVE" ]]; then
      grep ^"$YOMTOVE" "$STORDIR"/YomTove.cvs
      # actions based on what holiday it is
    fi
done
Next_Day

exit

rbees · 02-13-2015, 02:52 PM

I did get it figured out. Now I have a different problem. Time for a new thread with a more relevant topic

Thanks again

grail · 02-14-2015, 02:25 AM

Please remember to mark your threads as SOLVED.

I would also suggest an editor that has syntax highlighting as all I did was place your code in vim and format it

NevemTeve · 02-14-2015, 09:59 AM

Another suggestion:

instead of this:

Code:

elif [ ${DAY} = ${FULL} -a ${MONTH} = "12" ]; then

I suggest this:

Code:

elif [ "$DAY" = "$FULL" -a "$MONTH" = '12' ]; then