a script from a tutorial on strike

[vakimova]

dear sages,
please tell me what's wrong with the following script:

#!/bin/sh
#usage yd2ymd 1998213
# if there is no command line argument, assume one is being
# piped in and read it
if [ X$1 = X ]
then
read dt
else
dt=$1
fi

# break apart the year and the days

y=`expr $dt / 1000`
d=`expr $dt % 1000`

# subtract the number of days in each month starting from 1
# from the days in the date. When the day goes below 1, you
# have the current month. Add back the number of days in the
# month to get the correct day of the month
m=1
while [ `expr $d \> 0` = 1 ]
do
md=`sh monthdays $y $m`
d=`expr $d \- $md`
m=`expr $m \+ 1`
done

d=`expr $d \+ $md`

# the loop steps one past the correct month, so back up the month
m=`expr $m \- 1`

# assemble the results into a gregorian date
grg=`expr \( $y \* 10000 \) \+ \( $m \* 100 \) \+ $d`
echo $grg

---------------------
and all that resulted in --
---------------------
yd2ymd: 38: Syntax error: end of file unexpected (expecting "do")
# % >

Note: the script was copied from a tutorial, I only added "sh" in the line--
md=`monthdays $y $m`

to avoid "not found" message; the monthdays file is in its place and working OK.

yours`
serguey

 

[RMGBELGIUM]

at the end of your "do" routine, shouldn't there be "done"?

rgds,

R.

 

[vakimova]

Dear R.,

You are right "done" should be there and it is to the best of my sight:

do
md=`sh monthdays $y $m`
d=`expr $d \- $md`
m=`expr $m \+ 1`
done
^
|

Thank you for your try to help.

yours`
serguey

 

[feherke]

Hi

Works for me, with a fake monthdays. ( monthdays just returns hardcoded value of 30, the input number varies. )

I think the error is somewhere else, the code you posted is correct.

The excessive use of [tt]expr[/tt] makes the script obscure. My suggestion is to rewrite it, doing the arithmetic and relational operations with the shell itself.

Feherke.

http://rootshell.be/~feherke/

 

[p5wizard]

Are you sure you are running YOUR copy of yd2ymd? Try

type yd2ymd

and see where your shell finds a copy of the script to run.

If that checks out - try adding a 'set -x' at the top of the script - that way you'll be able to identify where it stuffs up. Also you'll know the args to monthdays because I am not at all convinced that script is 'working OK'. Also put a 'set -x' in the monthdays script too for further problem isolation.


HTH,

p5wizard

 

[motoslide]

Long shot: Any chance you have incorrect line termination in this file? Make sure you don't have ^M at the end of the lines.

 

[vakimova]

dear Feherke,

you are right -- the script should work for it is copied from a tutorial.
Unfortunately, I am not prepared yet to rewrite obscure scripts yet.

Thank you for your kind attention.

yours`
serguey

 

[vakimova]

dear p5 wizard,
the script is not MINE. I copied it from a tutorial, made a file of it, made the file executable with the command
chmod a+x yd2ymd
the same way I did to monthdays file which runs on its own quite OK.

Thank you for your help.

yours`
serguey

 

[vakimova]

dear motoslide,
the bulleye! I had lots of ^Ms in the file but erased all of them with vi editor and now there are no ^Ms to get rid of. So what?

admiredly yours`
serguey

 

[Annihilannic]

Does that mean the problem is fixed?

Did it work before you added the sh? Try changing it to sh -x perhaps, maybe the problem is in monthdays.

Annihilannic.

 

[vakimova]

dear Annihillanic,

the problem is not fixed and here is the whole story--

I ran across a bunch of scripts in a tutorial, typed them, 'chmod a-X'ed them and they all work except for this unfixed one.

To make sure it's not because of my typos I copied the script from the tutorial, pasted it (here ^Ms enter the story) and what I had for my pains is put at the start of this thread.
Any remedies I applied since then (both recommended and self-invented) have only been increasing the number of errors and illegal options.

Who ever told learning unix is better than running a darned farm?!

 

[p5wizard]

So, go back to your original version (remove the ^M-s)

add the "sh " if you like (better is to add "sh -x " for debugging purposes) to the monthdays line.

then run your script as follows (make sure you are in the directory containing both scripts):

sh -x yd2ymd 1998213

You'll get a whole lot of debugging info, and if you can't make sense of it all - post the output back here and let us have a look at it.


HTH,

p5wizard

 

[vakimova]

dear p5wizard,
thank you for talking business.
Here you are:
=============
Script started on Fri Dec 30 17:17:12 2005
# sh -x yd2ymd 1998321
+ [ X1998321 = X ]
+ dt=1998321
+ expr 1998321 / 1000
+ y=1998
+ expr 1998321 % 1000
+ d=321
+ m=1
+ expr 321 > 0
+ [ 1 = 1 ]
+ sh -x monthdays 1998 1
+ [ X1998 = X ]
+ [ X1 = X ]
+ expr ( 1998 * 10000 ) + ( 1 * 100 ) + 1
+ ymd=19980101
+ expr 19980101 / 10000
+ y=1998
+ expr ( 19980101 % 10000 ) / 100
+ m=1
+ echo 31
+ exit
+ md=31
+ expr 321 - 31
+ d=290
+ expr 1 + 1
+ m=2
+ expr 290 > 0
+ [ 1 = 1 ]
+ sh -x monthdays 1998 2
+ [ X1998 = X ]
+ [ X2 = X ]
+ expr ( 1998 * 10000 ) + ( 2 * 100 ) + 1
+ ymd=19980201
+ expr 19980201 / 10000
+ y=1998
+ expr ( 19980201 % 10000 ) / 100
+ m=2
+ sh yeardays 1998
+ diy=365
+ echo 28
+ exit
+ md=28
+ expr 290 - 28
+ d=262
+ expr 2 + 1
+ m=3
+ expr 262 > 0
+ [ 1 = 1 ]
+ sh -x monthdays 1998 3
+ [ X1998 = X ]
+ [ X3 = X ]
+ expr ( 1998 * 10000 ) + ( 3 * 100 ) + 1
+ ymd=19980301
+ expr 19980301 / 10000
+ y=1998
+ expr ( 19980301 % 10000 ) / 100
+ m=3
+ echo 31
+ exit
+ md=31
+ expr 262 - 31
+ d=231
+ expr 3 + 1
+ m=4
+ expr 231 > 0
+ [ 1 = 1 ]
+ sh -x monthdays 1998 4
+ [ X1998 = X ]
+ [ X4 = X ]
+ expr ( 1998 * 10000 ) + ( 4 * 100 ) + 1
+ ymd=19980401
+ expr 19980401 / 10000
+ y=1998
+ expr ( 19980401 % 10000 ) / 100
+ m=4
+ echo 30
+ exit
+ md=30
+ expr 231 - 30
+ d=201
+ expr 4 + 1
+ m=5
+ expr 201 > 0
+ [ 1 = 1 ]
+ sh -x monthdays 1998 5
+ [ X1998 = X ]
+ [ X5 = X ]
+ expr ( 1998 * 10000 ) + ( 5 * 100 ) + 1
+ ymd=19980501
+ expr 19980501 / 10000
+ y=1998
+ expr ( 19980501 % 10000 ) / 100
+ m=5
+ echo 31
+ exit
+ md=31
+ expr 201 - 31
+ d=170
+ expr 5 + 1
+ m=6
+ expr 170 > 0
+ [ 1 = 1 ]
+ sh -x monthdays 1998 6
+ [ X1998 = X ]
+ [ X6 = X ]
+ expr ( 1998 * 10000 ) + ( 6 * 100 ) + 1
+ ymd=19980601
+ expr 19980601 / 10000
+ y=1998
+ expr ( 19980601 % 10000 ) / 100
+ m=6
+ echo 30
+ exit
+ md=30
+ expr 170 - 30
+ d=140
+ expr 6 + 1
+ m=7
+ expr 140 > 0
+ [ 1 = 1 ]
+ sh -x monthdays 1998 7
+ [ X1998 = X ]
+ [ X7 = X ]
+ expr ( 1998 * 10000 ) + ( 7 * 100 ) + 1
+ ymd=19980701
+ expr 19980701 / 10000
+ y=1998
+ expr ( 19980701 % 10000 ) / 100
+ m=7
+ echo 31
+ exit
+ md=31
+ expr 140 - 31
+ d=109
+ expr 7 + 1
+ m=8
+ expr 109 > 0
+ [ 1 = 1 ]
+ sh -x monthdays 1998 8
+ [ X1998 = X ]
+ [ X8 = X ]
+ expr ( 1998 * 10000 ) + ( 8 * 100 ) + 1
+ ymd=19980801
+ expr 19980801 / 10000
+ y=1998
+ expr ( 19980801 % 10000 ) / 100
+ m=8
+ echo 31
+ exit
+ md=31
+ expr 109 - 31
+ d=78
+ expr 8 + 1
+ m=9
+ expr 78 > 0
+ [ 1 = 1 ]
+ sh -x monthdays 1998 9
+ [ X1998 = X ]
+ [ X9 = X ]
+ expr ( 1998 * 10000 ) + ( 9 * 100 ) + 1
+ ymd=19980901
+ expr 19980901 / 10000
+ y=1998
+ expr ( 19980901 % 10000 ) / 100
+ m=9
+ echo 30
+ exit
+ md=30
+ expr 78 - 30
+ d=48
+ expr 9 + 1
+ m=10
+ expr 48 > 0
+ [ 1 = 1 ]
+ sh -x monthdays 1998 10
+ [ X1998 = X ]
+ [ X10 = X ]
+ expr ( 1998 * 10000 ) + ( 10 * 100 ) + 1
+ ymd=19981001
+ expr 19981001 / 10000
+ y=1998
+ expr ( 19981001 % 10000 ) / 100
+ m=10
+ echo 31
+ exit
+ md=31
+ expr 48 - 31
+ d=17
+ expr 10 + 1
+ m=11
+ expr 17 > 0
+ [ 1 = 1 ]
+ sh -x monthdays 1998 11
+ [ X1998 = X ]
+ [ X11 = X ]
+ expr ( 1998 * 10000 ) + ( 11 * 100 ) + 1
+ ymd=19981101
+ expr 19981101 / 10000
+ y=1998
+ expr ( 19981101 % 10000 ) / 100
+ m=11
+ echo 30
+ exit
+ md=30
+ expr 17 - 30
+ d=-13
+ expr 11 + 1
+ m=12
+ expr -13 > 0
expr: illegal option -- 1
usage: expr [-e] expression
+ [ = 1 ]
[: =: unexpected operator
+ expr -13 + 30
expr: illegal option -- 1
usage: expr [-e] expression
+ d=
+ expr 12 - 1
+ m=11
+ expr ( 1998 * 10000 ) + ( 11 * 100 ) +
expr: syntax error
+ grg=
+ echo
=======================================
By the by, what does your "HTH" mean?

yours`
serguey

 

[Annihilannic]

What operating system is this on? expr doesn't behave that way on any of the operating systems I have tried...

Try changing it to expr -e, perhaps that will prevent it from treating -13 as an option/switch.

HTH means "Hope That Helps".

Annihilannic.

 

[p5wizard]

looks like your UNIX version's impementation of expr doesn't like "expr -13 + 30" or "expr -17 \> 0".

Your expr assumes an option or flag follows the dash or minus sign.

Perhaps you can circumvent the problem:

try modifying line 22 into:

while [ `expr 0 + $d \> 0` = 1 ]

and see how far you get.

Hope This Helps,

p5wizard.

 

[PHV]

And why not simply this ?
while [ "$d" -gt 0 ]

Hope This Helps, PH.
Want to get great answers to your Tek-Tips questions? Have a look at FAQ219-2884 or FAQ181-2886

 

[p5wizard]

Yes, of course PHV. But I was aiming for a minimal modification. And as this is a script from a tutorial, it looks to me as being an "expr" script exercise...


HTH,

p5wizard

 

[vakimova]

dear Annihilannic,

before your question I was sure my OS was fbsd-5.3, but now I just suppose it is so.
I crammed "-e" in after each "expr" I could see in the script yet the message "usage: expr [-e] expression" popped up again.
Thank you for your explaining of "HTH".

yours`
serguey

 

[vakimova]

dear p5wizard,

adding "0 \+" before "$d" as you proposed took me some six lines further where I repeated the trick you prompted and the whole script worked! IWI!

"IWI" = It Works Indeed

please receive my gratitude and endless admiration

yours`
serguey

 

[vakimova]

dear PHV,

of course you are right: the modification you proposed eliminated the problem and the script worked OK.
Thank you for the insight and the lead to FAQs.

much obliged
yours`
serguey