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Full Discussion: display echo only once
Top Forums Shell Programming and Scripting display echo only once Post 302630427 by agama on Wednesday 25th of April 2012 08:40:55 PM
Old 04-25-2012
You have a couple of options. Test before entering the for loop and exit immediately after writing the error message:

Code:
if (( $# < 1 ))
then
   echo "you must enter a name to convert"
   exit
fi

ls *.jpg | while read img
do
    jpegtopnm "$img" | pnmscale -height 200 | pnmtojpeg > "${1%.jpg}-thumb.jpg"
done



However, since you are not using the information on the command line it seems odd that you would require it be entered. Maybe you are intending to get parameters or something from the command line; if that is the case then this would allow for you to validate and continue if you get the information.

However, the message in your code implies that you want the user to enter an image file to convert. If they enter a file, do you want to just convert the ones on the command line, but default to converting everything if they don't enter any filename? If so, you could do something like this:

Code:
function mk_thumb
{
    # probably wise to add code to verify that $1 is an image file, exists etc.
    jpegtopnm "$img" | pnmscale -height 200 | pnmtojpeg > "${1%.jpg}-thumb.jpg"
}

if (( $# > 0 ))             # if command line parms, process just them
then
    while [[ -n $1 ]]
    do
        mk_thumb $1
        shift
    done
else                        # no parms, then convert all
    ls *.jpg | while read img
    do
        mk_thumb $img
    done
fi



This invokes the conversion function once for each command line parm (the function probably should verify that it exists and is a proper file type etc.). If no parameters are entered, then it invokes the function for all jpg files in the current directory.

I've not really tested either of these, but you should get an idea of your options.
 

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MSSQL_FETCH_FIELD(3)													      MSSQL_FETCH_FIELD(3)

mssql_fetch_field - Get field information

SYNOPSIS
object mssql_fetch_field (resource $result, [int $field_offset = -1]) DESCRIPTION
mssql_fetch_field(3) can be used in order to obtain information about fields in a certain query result. PARAMETERS
o $result - The result resource that is being evaluated. This result comes from a call to mssql_query(3). o $field_offset - The numerical field offset. If the field offset is not specified, the next field that was not yet retrieved by this function is retrieved. The $field_offset starts at 0. RETURN VALUES
Returns an object containing field information. The properties of the object are: o name - column name. if the column is a result of a function, this property is set to computed#N, where #N is a serial number. o column_source - the table from which the column was taken o max_length - maximum length of the column o numeric - 1 if the column is numeric o type - the column type. EXAMPLES
Example #1 mssql_fetch_field(3) example <?php // Connect to MSSQL and select the database mssql_connect('MANGOSQLEXPRESS', 'sa', 'phpfi'); mssql_select_db('php'); // Send a select query to MSSQL $query = mssql_query('SELECT * FROM [php].[dbo].[persons]'); // Construct table echo '<h3>Table structure for 'persons'</h3>'; echo '<table border="1">'; // Table header echo '<thead>'; echo '<tr>'; echo '<td>Field name</td>'; echo '<td>Data type</td>'; echo '<td>Max length</td>'; echo '</tr>'; echo '</thead>'; // Dump all fields echo '<tbody>'; for ($i = 0; $i < mssql_num_fields($query); ++$i) { // Fetch the field information $field = mssql_fetch_field($query, $i); // Print the row echo '<tr>'; echo '<td>' . $field->name . '</td>'; echo '<td>' . strtoupper($field->type) . '</td>'; echo '<td>' . $field->max_length . '</td>'; echo '</tr>'; } echo '</tbody>'; echo '</table>'; // Free the query result mssql_free_result($query); ?> SEE ALSO
mssql_field_seek(3). PHP Documentation Group MSSQL_FETCH_FIELD(3)
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