Bash scripting: value too great for base (error token is "08")

xsyntax · 08-06-2010, 03:27 PM

I have a bash script that I use to process some data, and compares each days file with the previous days file and store it in files based on the current date. The script needs to know yesterdays date and todays date stored in this format: YYYYMMDD. It runs every single day, and the script has worked flawlessly until I noticed this error today. It is getting an error for the month of August ("08"). I don't have logs to show if the error occured the first 5 days of August, but I would assume so.

The code is below, with the line causing the error in red.
OFFSET=${1:-1}

set DAYS Sat Sun Mon Tue Wed Thu Fri Sat
set MONTHS Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
YESTERDAYPRE=`date +%d | sed 's/^0*//'`
YESTERDAY=`expr $YESTERDAYPRE - 1`
#YESTERDAY=$((`date +%d` -1))
MONTH=`date +%m`
YEAR=`date +%Y`
NDAY=`date +%u`
WEEKDAY=${DAYS[`date +%u`]}
if [ $YESTERDAY -eq "0" ]
then
MONTH=$((MONTH-1))
if [ $MONTH -eq "0" ]
then
MONTH=12
YEAR=$((YEAR-1))
fi
set `cal $MONTH $YEAR`
shift $(($# - 1))
YESTERDAY=$1
fi
TMONTH=${MONTHS[MONTH]}
# echo $WEEKDAY $YESTERDAY $MONTH $TMONTH $YEAR
if [ $MONTH -eq "1" ] ; then MONTH=01 ; fi
if [ $MONTH -eq "2" ] ; then MONTH=02 ; fi
if [ $MONTH -eq "3" ] ; then MONTH=03 ; fi
if [ $MONTH -eq "4" ] ; then MONTH=04 ; fi
if [ $MONTH -eq "5" ] ; then MONTH=05 ; fi
if [ $MONTH -eq "6" ] ; then MONTH=06 ; fi
if [ $MONTH -eq "7" ] ; then MONTH=07 ; fi
if [ $MONTH -eq "8" ] ; then MONTH=08 ; fi
if [ $MONTH -eq "9" ] ; then MONTH=09 ; fi

if [ $YESTERDAY -eq "1" ] ; then YESTERDAY=01 ; fi
if [ $YESTERDAY -eq "2" ] ; then YESTERDAY=02 ; fi
if [ $YESTERDAY -eq "3" ] ; then YESTERDAY=03 ; fi
if [ $YESTERDAY -eq "4" ] ; then YESTERDAY=04 ; fi
if [ $YESTERDAY -eq "5" ] ; then YESTERDAY=05 ; fi
if [ $YESTERDAY -eq "6" ] ; then YESTERDAY=06 ; fi
if [ $YESTERDAY -eq "7" ] ; then YESTERDAY=07 ; fi
if [ $YESTERDAY -eq "8" ] ; then YESTERDAY=08 ; fi
if [ $YESTERDAY -eq "9" ] ; then YESTERDAY=09 ; fi

yesterday=$YEAR$MONTH$YESTERDAY
today=`date +%Y%m%d`

The if statements were added to keep everything in two digit format.

I don't have a ton of bash experience so I'm sure there are 100 much more efficient ways of doing this, LOL

Thanks!

David the H. · 08-06-2010, 04:12 PM

Please use [code][/code] tags around your scripts, to preserve formatting and to improve readability.

I haven't worked through everything yet, but it appears that somehow your MONTHS value is coming out as "08", and the leading zero in that is unusable as the index number in the TMONTH array variable.

As for your list of if statements, you can use something like this instead:

Code:

if [[ $MONTH =~ ^[1-9]$ ]] ; then
     MONTH=${MONTH/#/0}
fi

if [[ $YESTERDAY =~ ^[1-9]$ ]] ; then
     YESTERDAY=${YESTERDAY/#/0}
fi

It uses bash's more flexible extended test command, allowing the easy use of regex values, and parameter substitution to add the leading zero.

Oh, and $(..) is recommended over `..`

David the H. · 08-06-2010, 04:43 PM

I think I can say a bit more about it now. "date +%m" outputs the month in zero-padded form.

But bash treats integers starting with 0 as octal values, so you're ok from 01-07, but 08 and 09 are illegal in all of your arithmetic functions.

A quick glance at the date man page shows that, instead of using sed or other tricks, you can simply use a hyphen in the format string to force it not to zero-pad. e.g. "date +%-m".

Oh, and here's an even cleaner way to re-pad the numbers afterwards, using bash's builtin printf function:

Code:

MONTH=$(printf %02d $MONTH)
YESTERDAY=$(printf %02d $YESTERDAY)

Edit: And one last thing. I was puzzled about your two "set" lines at the beginning of the script, but now I see that they're supposed to be array values. But that's not how to populate an array. You need something like this instead:

Code:

DAYS=( Sat Sun Mon Tue Wed Thu Fri Sat )
MONTHS=( Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec )

After I made all the above changes, your script seems to give me the kind of output I'd expect it to.

David the H. · 08-06-2010, 05:50 PM

One last post. In retrospect, most of what you're attempting can be done with just the date command. GNU date can be set to output some other date instead of the current one. More here and here.

The following is just an example of how to fetch various strings for "yesterday". I've used an array, so as to only call date one time. The fewer external calls you have to make, the more efficient the code.

Code:

#!/bin/bash

YESTARRAY=( $(date -d "yesterday" "+%d %u %a %m %b %Y") )

YESTERDAY=${YESTARRAY[0]}
WEEKDAYNUM=${YESTARRAY[1]}
WEEKDAYSTR=${YESTARRAY[2]}

MONTHNUM=${YESTARRAY[3]}
MONTHSTR=${YESTARRAY[4]}
YEAR=${YESTARRAY[5]}

echo "Yesterday's date (day of month): $YESTERDAY"
echo "Day of the week in numeric form: $WEEKDAYNUM"
echo "Day of the week in abbreviated string form: $WEEKDAYSTR"
echo "Month in numeric form: $MONTHNUM"
echo "Month in abbreviated string form: $MONTHSTR"
echo "Year: $YEAR"

exit 0

And the output:

Code:

$ ./datescript.sh
Yesterday's date (day of month): 06
Day of the week in numeric form: 5
Day of the week in abbreviated string form: Fri
Month in numeric form: 08
Month in abbreviated string form: Aug
Year: 2010

Freddythunder · 05-08-2012, 12:36 PM

Thanks for this! I was using this whole friggin thing to get to yesterdays date

Code:

declare eod=(0 31 28 31 30 31 30 31 31 30 31 30 31)
yest=`date +%d`
yest=$((yest-1))
mon=`date +%m`
if [ $yest -lt 1 ]
then
        mon=$((mon-1))
        yest=${eod[$mon]}
fi
if [ $mon -lt 10 ] && [ ${#mon} -eq 1 ];
then
        mon=0$mon
fi
if [ $yest -lt 10 ] && [ ${#yest} -eq 1 ];
then
        yest=0$yest
fi

...and now it's one line of code. I know this post is two years old, but maybe you'll get a thanks in your email.