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Nested if with multiple conditions

 
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# 1  
Old 11-26-2010
Error Nested if with multiple conditions
Deal Experts

I am working on a script to find a date which is 7 days older and follwoing is my approach
Code:
#!/bin/sh
Yr=`date +"%Y"`
Mn=`date +"%m"`
Md=28
Da=`date +"%d"`
echo $Yr
echo $Mn
echo $Da
var1=$Yr$Mn$Da
echo "before" $var1
if expr $Da > 7
then Da=`expr $Da - 7`
var1=$Yr$Mn$Da
echo $var1
fi
if expr $Da <= 7
then 
if $`expr $Mn -1` < 1
then 
Mn=12
Yr=`expr $Yr - 1`
else 
Mn=`expr $Mn - 1`
fi
fi

it is giving error on line 16th saying
A file or directory in the path name does not exist.
Code:
Date.sh[16]: =: 0403-016 Cannot find or open the file.

I am not trying to open or access any file but still it is throwing the error

Please help

Moderator's Comments:
Mod Comment Please use code tags
Last edited by Scott; 11-26-2010 at 09:49 AM..
# 2  
Old 11-26-2010
Well, I think you are trying to say "What was the date 7 days ago.

If so, then try this neat trick by bending the timezone back to extremes:-
Code:
#!bin/ksh
REAL_TZ=$TZ
TZ=CUT168
date "+%d %m %Y"|read dd mm yyyy
TZ=$REAL_TZ
echo "Today is `date +%d/%m/%Y` but 7 days ago it was $dd/$mm/$yyyy"

The value of TZ=CUT168 says "read the system clock and set it to Coordinated Universal Time (aka Zulu or GMT) and go back 168 hours" i.e. 7x24 hours.
Remember to reset the TZ after the tweak or all your trace and logging may get very confusing.


I hope that this helps. If not, please let me know what I've missed.



Robin
Liverpool/Blackburn
UK
Last edited by rbatte1; 11-26-2010 at 10:16 AM.. Reason: Make the date output the same in the echo statement.
# 3  
Old 11-26-2010
Hi

As a newbee I donot know how to reset the TZ to current
Can I add the reset the original at the end of the code?
can you tell me that before I try your solution

Thanks
# 4  
Old 11-29-2010
The line
Code:
REAL_TZ=$TZ

records the setting you start with and then the reverse
Code:
TZ=$REAL_TZ

puts is back afterwards, hence why I have added the echo statement at the end to show that it has been done correctly.

Give it a bash. It doesn't do anything dangerous with the real clock, just your view in your session. If it goes wrong, close that session and open a new one and all will be back as normal.

If you save the above as rbatte1.script and you have any problems, paste the output from
Code:
ksh -x rbatte1.script

back into this thread and I will have a closer look.Smilie




Robin
 
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