Unix Programming - Batch file in Unix

Author

Batch file in Unix

L Benoit

2008-01-18, 7:14 pm

G'day,

I'm a newbie to Unix (and programming at all).

The situation is: I have a C-program "MyProgram" which
depends on an integer parameter z.
MyProgram is running on a Unix machine.

Currently I'm typing

MyProgram -z > MyResults.txt

and the result is written in the file "MyResults.txt".

Since I have a large number of various parameter z to be put
into MyProgram I cannot do it manually.
Also, I cannot change the code of MyProgram as I do not
have the source code available.

Therefore I'm thinking of writing a little program
which produces command lines like

MyProgram -z1 > MyResults.txt
MyProgram -z2 > MyResults.txt
....
MyProgram -zn > MyResults.txt

These command lines are then to be stored into one file,
say "MyCommands.txt".

Question:
1. How can I get Unix to execute each command line
of MyCommands.txt?
2. I suspect that each new result will overwrite
the previous result. So how can I make sure that
the new result is *only added* to the previous
ones in the same file "MyResults.txt"?

Thanks a lot,
L

Ben Bacarisse

2008-01-18, 7:14 pm

L Benoit <legendre_benoit@yahoo.ca> writes:

> The situation is: I have a C-program "MyProgram" which
> depends on an integer parameter z.
> MyProgram is running on a Unix machine.
>
> Currently I'm typing
>
> MyProgram -z > MyResults.txt
>
> and the result is written in the file "MyResults.txt".
>
> Since I have a large number of various parameter z to be put
> into MyProgram I cannot do it manually.
> Also, I cannot change the code of MyProgram as I do not
> have the source code available.
>
> Therefore I'm thinking of writing a little program
> which produces command lines like
>
> MyProgram -z1 > MyResults.txt
> MyProgram -z2 > MyResults.txt
> ...
> MyProgram -zn > MyResults.txt

No need to write a program to do that unless the pattern of the zn is
very complex. Real examples would help (i.e. dod you just want 0, 1,
2, 3 and so on or 8723, 546381, -265347, etc?).

> These command lines are then to be stored into one file,
> say "MyCommands.txt".
>
> Question:
> 1. How can I get Unix to execute each command line
> of MyCommands.txt?

Put:

#!/bin/sh

at the top and make it executable (chmod +x MyCommands.txt). Of
course you can just ask a shell to read it:

sh MyCommands.txt

(or bash, or csh, or zsh, ...)

> 2. I suspect that each new result will overwrite
> the previous result. So how can I make sure that
> the new result is *only added* to the previous
> ones in the same file "MyResults.txt"?

change > to >> and you get appending.

--
Ben.

Chris F.A. Johnson

2008-01-18, 7:14 pm

On 2008-01-18, L Benoit wrote:
>
> I'm a newbie to Unix (and programming at all).
>
> The situation is: I have a C-program "MyProgram" which
> depends on an integer parameter z.
> MyProgram is running on a Unix machine.
>
> Currently I'm typing
>
> MyProgram -z > MyResults.txt
>
> and the result is written in the file "MyResults.txt".
>
> Since I have a large number of various parameter z to be put
> into MyProgram I cannot do it manually.
> Also, I cannot change the code of MyProgram as I do not
> have the source code available.
>
> Therefore I'm thinking of writing a little program
> which produces command lines like
>
> MyProgram -z1 > MyResults.txt
> MyProgram -z2 > MyResults.txt
> ...
> MyProgram -zn > MyResults.txt
>
> These command lines are then to be stored into one file,
> say "MyCommands.txt".
>
> Question:
> 1. How can I get Unix to execute each command line
> of MyCommands.txt?

Give the file executable status:

chmod +x MyCommands.txt

Then call it as you would any other program. Either put it in a
directory that's in your PATH (e.g., $HOME/bin) or give the path to
the file (e.g., ./MyCommands.txt).

> 2. I suspect that each new result will overwrite
> the previous result. So how can I make sure that
> the new result is *only added* to the previous
> ones in the same file "MyResults.txt"?

Enclose the commands in braces to make it a compound command and
redirect its output:

{
MyProgram -z1
MyProgram -z2
...
MyProgram -zn
} > MyResults.txt

--
Chris F.A. Johnson, author | <http://cfaj.freeshell.org>
Shell Scripting Recipes: | My code in this post, if any,
A Problem-Solution Approach | is released under the
2005, Apress | GNU General Public Licence

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