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Full Discussion: detecting the part of a filename
Top Forums Shell Programming and Scripting detecting the part of a filename Post 302259281 by jim mcnamara on Monday 17th of November 2008 05:13:15 PM
Old 11-17-2008
That was in lieu of this, dates are messy
Code:
echo $filename | \
 sed  's/\(^[1-2][0-9]\{3\}\)-\([0-1][0-9]\)-\([0-3][0-9]\)-\([A-Z_0-9a-z]*\)/\4/'  | read newfilename
if [[ ! -z newfilename ]] ; then
   filename=$newfilename
fi

Basically I would suggest that naming every file with a leading date has problems. try
ls -l instead. Chris was technically correct -no doubt - but the usefulness of the above is limited. In part this is due to the way dates are constructed - and the above regex is not perfect. It will think 2008-19-19 is a date - which it is not. Most correct date regexes are several hundred character long. The only gold standard is to refer to the output of cal.


We use part of this date check algorithm below (simplified greatly) for validating old dates. This is more nearly complete && correct than most straight shell implementations using regex are likely to be. I deliberately excluded


Code:
/* chpdt.c 
usage chpdt filename 
      echo "$filname" | chpdt
*/
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <stdio.h>
#define isleapyr(y) (((y) % 4) == 0 && ((y) % 100) != 0 || ((y) % 400) == 0)
int leap[12]= {31,29,31,30,31,30,31,31,30,31,30,31};
int nleap[12]={31,28,31,30,31,30,31,31,30,31,30,31};


char  *date_ok(char *result, char *src)
{
	int value=atoi(src);
	int month=0;
	char *p=src;
	int *v=nleap;

    if( value >= 1900 && value < 2038 && (p=strchr(p, '-')) != NULL )
    {
        if(isleapyr(value))        
        	v=leap;
		value=atoi(++p);
		if(value >= 1 && value < 13 && (p=strchr(p, '-')) != NULL)
		{
			month=value;
			value=atoi(++p);
			if( value > 0 && value < v[ month - 1 ] )
				if( (p=strchr(p, '-')) != NULL)
					result=++p;
		}
    }
    return result;
}

char  *name_ok(char *p, char *src)
{
	if(src[4]=='-' && src[7]=='-' && src[10]=='-')
		p=date_ok(p, src);
	return p;
}

int main(int argc, char **argv)
{
	int retval=0;
	char tmp[PATH_MAX + 2]={0x0};
	char *p=NULL;
	if (argc < 2)
	{
		if(fgets(tmp, sizeof(tmp), stdin) ==NULL)
		{
			perror("I/O error");
			retval=1;
		};
		p=strchr(tmp, '\n');
		if(p!=NULL)
			*p=0x0;
	}
	else
		(void)strncpy(tmp, argv[1], PATH_MAX);
	p=tmp;
	if(strlen(tmp) > 10 && !retval) /* will return zero length if string is "date-"*/
		p=name_ok(p, tmp);
    if( fprintf(stdout, "%s", p) < 0)
    {
    	perror("I/O error");
    	retval=1;	
    }
    return retval;
}

Good luck with this.
 

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LEARN ABOUT HPUX

ftpconversions

ftpconversions(4)					     Kernel Interfaces Manual						 ftpconversions(4)

NAME

       ftpconversions - ftpd conversions database

SYNOPSIS

DESCRIPTION

       The  conversions  known	by and their attributes are stored in an ASCII file that is structured as below.  Each line in the file provides a
       description for a single conversion.  Fields are separated by colons (:).

       Field   Description
       1       strip prefix
       2       strip postfix
       3       addon prefix
       4       addon postfix
       5       external command
       6       types
       7       options
       8       description

       strip postfix and addon postfix can be the file extensions or or or The file extensions the ftp server supports and the action that the ftp
       server performs is summarized in the table below. This feature is supported only when using the command.
		     |			  |
       True Filename | Specified Filename | Action
       --------------+--------------------+---------------------------------------
       filename.Z    | filename 	  | Decompress file before transmitting
       filename      | filename.Z	  | Compress filename before transmitting
       filename      | filename.tar	  | Tar filename before transmitting
       filename      | filename.tar.Z	  | Tar and compress filename
		     |			  | before transmitting

       external  command field is used to specify the path of the program/script to be used to perform the action specified for the different file
       extensions as described in the above table.

       types field indicates the flags that must be checked before compressing, decompressing, tarring and untarring the  file	requested  by  the
       command.

       options field specifies the options for the program/script specified in the external command field.

       description is a short description of each conversion.

       NOTE:  The  HP-UX command does not support any option to do or If the user wants to perform any such action, he/she must then write his/her
       own program/script to do it and specify the pathname of the program/script in the external command field in the file. Also a  copy  of  the
       programs/scripts  used  to  perform  the conversions and the respective libraries used by the programs/scripts must be copied into the home
       directory of each of the and user accounts for the and users to be able to perform on-the-fly conversions.

WARNINGS

       The conversions mechanism does not currently support the strip prefix and addon prefix fields.

FILES

AUTHOR

       was developed by the Washington University, St. Louis, Missouri.

SEE ALSO

       ftpd(1M), ftpaccess(4).

																 ftpconversions(4)
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