Re: SH programming
On Sun, 26 Jun 2005, Peter Bako wrote: Ok, so this is not really an OpenBSD question but I am doing this on an OpenBSD system and I am about to lose my mind... I have done some basic shell scripting before but I've not had to deal with actual integer math before and now it is killing me. The script takes a parameter in (year number) and is supposed to subtract 1900 from it and then multiply the result by 365. (This is part of a larger script that deal with converting dates to a single numeric value, but this one problem is an example of the problems I am having with this entire script.) So, this is what I have: #!/bin/sh month=$1 day=$2 year=$3 dayscount=$(expr ($year - 1900) * 365) echo $dayscount exit This will generate a syntax error: `$year' unexpected error. I have tried all sorts of variations and I am not getting it!!! HELP!!! When using ksh, you can do: #!/bin/ksh month=$1 day=$2 year=$3 dayscount=$((($year - 1900) * 365)) echo $dayscount exit When using sh, you'll need expr(1), for which all parts of the expression are separate arguments, and you need to escape all special shell chars: #!/bin/sh month=$1 day=$2 year=$3 dayscount=`expr \( $year - 1900 \) \* 365` echo $dayscount exit BTW, obviously I need a good book on SH programming. Any suggestions? For ksh, the Korn Shell Book by David Korn and (iirc Morris Bolsky) comes to mind. -Otto
Re: SH programming
The following seems to work. $ year=2005 $ foo=$(expr $year - 1900 ) $ dayscount=$(expr $foo \* 365 ) $ echo $dayscount 38325 Problems include an unescaped asterisk man expr indicates that parentheses should work but my playing with them seems to indicate otherwise. ---Correction: $ dayscount=$(expr \( $year - 1900 \) \* 365 ) $ echo $dayscount 38325 Parens that are destined for expr instead of the shell must also be escaped. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Otto Moerbeek Sent: Monday, June 27, 2005 2:08 AM To: Peter Bako Cc: misc@openbsd.org Subject: Re: SH programming On Sun, 26 Jun 2005, Peter Bako wrote: Ok, so this is not really an OpenBSD question but I am doing this on an OpenBSD system and I am about to lose my mind... I have done some basic shell scripting before but I've not had to deal with actual integer math before and now it is killing me. The script takes a parameter in (year number) and is supposed to subtract 1900 from it and then multiply the result by 365. (This is part of a larger script that deal with converting dates to a single numeric value, but this one problem is an example of the problems I am having with this entire script.) So, this is what I have: #!/bin/sh month=$1 day=$2 year=$3 dayscount=$(expr ($year - 1900) * 365) echo $dayscount exit This will generate a syntax error: `$year' unexpected error. I have tried all sorts of variations and I am not getting it!!! HELP!!! When using ksh, you can do: #!/bin/ksh month=$1 day=$2 year=$3 dayscount=$((($year - 1900) * 365)) echo $dayscount exit When using sh, you'll need expr(1), for which all parts of the expression are separate arguments, and you need to escape all special shell chars: #!/bin/sh month=$1 day=$2 year=$3 dayscount=`expr \( $year - 1900 \) \* 365` echo $dayscount exit BTW, obviously I need a good book on SH programming. Any suggestions? For ksh, the Korn Shell Book by David Korn and (iirc Morris Bolsky) comes to mind. -Otto
Re: SH programming
On Mon, 27 Jun 2005 [EMAIL PROTECTED] wrote: The following seems to work. $ year=2005 $ foo=$(expr $year - 1900 ) $ dayscount=$(expr $foo \* 365 ) $ echo $dayscount 38325 Problems include an unescaped asterisk man expr indicates that parentheses should work but my playing with them seems to indicate otherwise. ---Correction: $ dayscount=$(expr \( $year - 1900 \) \* 365 ) $ echo $dayscount 38325 Parens that are destined for expr instead of the shell must also be escaped. And this is almost exaclty the sh script I sent in my reply. The escaping of parentheses is obviously needed to avoid them being interpreted by the shell. That is standard shell programming stuff. And please do not toppost. -Otto -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Otto Moerbeek Sent: Monday, June 27, 2005 2:08 AM To: Peter Bako Cc: misc@openbsd.org Subject: Re: SH programming On Sun, 26 Jun 2005, Peter Bako wrote: Ok, so this is not really an OpenBSD question but I am doing this on an OpenBSD system and I am about to lose my mind... I have done some basic shell scripting before but I've not had to deal with actual integer math before and now it is killing me. The script takes a parameter in (year number) and is supposed to subtract 1900 from it and then multiply the result by 365. (This is part of a larger script that deal with converting dates to a single numeric value, but this one problem is an example of the problems I am having with this entire script.) So, this is what I have: #!/bin/sh month=$1 day=$2 year=$3 dayscount=$(expr ($year - 1900) * 365) echo $dayscount exit This will generate a syntax error: `$year' unexpected error. I have tried all sorts of variations and I am not getting it!!! HELP!!! When using ksh, you can do: #!/bin/ksh month=$1 day=$2 year=$3 dayscount=$((($year - 1900) * 365)) echo $dayscount exit When using sh, you'll need expr(1), for which all parts of the expression are separate arguments, and you need to escape all special shell chars: #!/bin/sh month=$1 day=$2 year=$3 dayscount=`expr \( $year - 1900 \) \* 365` echo $dayscount exit BTW, obviously I need a good book on SH programming. Any suggestions? For ksh, the Korn Shell Book by David Korn and (iirc Morris Bolsky) comes to mind. -Otto
Re: SH programming
Try escaping the * \* Peter Bako wrote: Hum, I get a syntax error: '*' unexpected -Original Message- From: Michael Erdely [mailto:[EMAIL PROTECTED] Sent: Sunday, June 26, 2005 6:20 PM To: Peter Bako Cc: misc@openbsd.org Subject: Re: SH programming On 6/26/05, Peter Bako [EMAIL PROTECTED] wrote: dayscount=$(expr ($year - 1900) * 365) Try: dayscount=$((($year - 1900) * 365))
SH programming
Ok, so this is not really an OpenBSD question but I am doing this on an OpenBSD system and I am about to lose my mind... I have done some basic shell scripting before but I've not had to deal with actual integer math before and now it is killing me. The script takes a parameter in (year number) and is supposed to subtract 1900 from it and then multiply the result by 365. (This is part of a larger script that deal with converting dates to a single numeric value, but this one problem is an example of the problems I am having with this entire script.) So, this is what I have: #!/bin/sh month=$1 day=$2 year=$3 dayscount=$(expr ($year - 1900) * 365) echo $dayscount exit This will generate a syntax error: `$year' unexpected error. I have tried all sorts of variations and I am not getting it!!! HELP!!! BTW, obviously I need a good book on SH programming. Any suggestions? Thanks, Peter
Re: SH programming
On Sun, 26 Jun 2005, Peter Bako wrote: #!/bin/sh month=$1 day=$2 year=$3 dayscount=$(expr ($year - 1900) * 365) echo $dayscount exit This will generate a syntax error: `$year' unexpected error. I have tried all sorts of variations and I am not getting it!!! HELP!!! man sh says arithmetic expressions take double parens: dayscount=$((($year - 1900) * 365)) don't forget about leap years. -- And that's why we need security.
Re: SH programming
Hum, I get a syntax error: '*' unexpected -Original Message- From: Michael Erdely [mailto:[EMAIL PROTECTED] Sent: Sunday, June 26, 2005 6:20 PM To: Peter Bako Cc: misc@openbsd.org Subject: Re: SH programming On 6/26/05, Peter Bako [EMAIL PROTECTED] wrote: dayscount=$(expr ($year - 1900) * 365) Try: dayscount=$((($year - 1900) * 365)) -- http://erdelynet.com/ Support OpenBSD! http://www.openbsd.org/orders.html
Re: SH programming
On Sun, Jun 26, 2005 at 09:32:36PM -0400, Ted Unangst wrote: On Sun, 26 Jun 2005, Peter Bako wrote: #!/bin/sh month=$1 day=$2 year=$3 dayscount=$(expr ($year - 1900) * 365) echo $dayscount exit This will generate a syntax error: `$year' unexpected error. I have tried all sorts of variations and I am not getting it!!! HELP!!! man sh says arithmetic expressions take double parens: dayscount=$((($year - 1900) * 365)) don't forget about leap years. Traditional Bourne shell doesn't have arithmetic substitutions so it would be done with expr like this: dayscount=$(expr $(expr $year - 1900) \* 365) or even: dayscount=`expr \`expr $year - 1900\` \* 365` This only matters if your script needs to be portable. -- stephen
Re: SH programming
On Sun, 26 Jun 2005 20:51:07 -0700, Peter Bako wrote: Hum, I get a syntax error: '*' unexpected IJWFM using sh or ksh on 3.7 i386 entering year and the calc line at the prompt and echoing $daycount at the prompt. -Original Message- From: Michael Erdely [mailto:[EMAIL PROTECTED] Sent: Sunday, June 26, 2005 6:20 PM To: Peter Bako Cc: misc@openbsd.org Subject: Re: SH programming On 6/26/05, Peter Bako [EMAIL PROTECTED] wrote: dayscount=$(expr ($year - 1900) * 365) Try: dayscount=$((($year - 1900) * 365)) -- http://erdelynet.com/ Support OpenBSD! http://www.openbsd.org/orders.html From the land down under: Australia. Do we look umop apisdn from up over? Do NOT CC me - I am subscribed to the list. Replies to the sender address will fail except from the list-server.
