SUMMARY

Sets wildcard characters used in read commands to expand filelists.

SYNTAX

WILD {ECHO {ON|OFF}},{SINGLE char},{MULTIPLE char},
    {CONCATENATION chars}

INPUT

ECHO {ON}:	Turn echoing of expanded filelist on. Echoing is only when this option is on and there are wildcard characters in the filelist.
ECHO OFF:	Turn echoing of expanded filelist off.
SINGLE char:	Change the character used to match single characters.
MULTIPLE char:	Change the character used to match multiple characters.
CONCATENATION chars:
	Change the two characters used to enclose concatenation lists.

DEFAULT VALUES

OPTION	UNIX	VAX	PRIME
ECHO	ON	ON	ON
SINGLE	?	?	+
MULTIPLE	*	*	'
CONCATENATION	[,]	(,)	[,]

DESCRIPTION

This feature is available at the command level of many modern operating systems and is called "wildcarding" or "filename expansion." It is a notation that allows you to abbreviate filenames and to specify entire groups of files using a simple shorthand notation. SAC has implemented wildcarding, along with several extensions, in its READ, READALPHA, and READHDR commands. Using this notation, you can easily access lists such as:

• All files beginning with the letters "abc".
• All files ending with the letter "z".
• All files with exactly three letters in their names.

There are three elements in this wildcard notation. We will use the default wildcard characters for the UNIX version in this description and in the examples below. The defaults may be different on the computer you are using. You may also use this command to change the characters to be anything you want. The multiple match character ("*") is used to match an arbitrary character string, including an empty string. The single match character ("?") is used to match any single character. The concatenation characters ("[" and "]") are used to enclose a comma delimited list of character strings to match. The character strings in a concatenation list may not contain the single or multiple match wildcard characters. These are the steps that SAC uses to perform this wildcard filename expansion:

1. Strip away the directory part of the token if it exists. Otherwise use the current directory.
2. Make a system call to get a list of all files in the directory.
3. If a concatenation list is in the token, form new tokens from each character string in the concatenation list with the other characters in the token and then match them to the list of files. If there is no concatenation list in the token, simply match the token to the list of files.
4. Remove any duplicates matches to form the expanded filelist.
5. Echo the expanded filelist if requested.
6. Attempt to read the expanded filelist into memory.

Each operating system uses a somewhat different scheme to store and access files in a directory. The system call in (1) above reflects these differences. For example, the filenames are returned in alphabetical order in UNIX but are not on the PRIME or VAX. The order of the files in a PRIME directory is arbitrary. These differences are reflected in the order of the files in the expanded filelist. You may have to experiment with different variations of wildcard characters and concatenation lists if the order of the files in the expanded list is important.

The examples below will help clarify how to use these wildcard elements. One useful feature is that SAC saves the character strings contained in the concatenation list. When you enter an empty list, then the previous list is reused. This can save a lot of typing.

EXAMPLES

Assume that the contents of the current directory contain the following files in the order shown:

ABC   DEF   STA01E   STA01N   STA01Z   STA02E   STA02N   STA02Z   STA03Z

Also, assume that expanded filelist echoing is on. The following shows how the various wildcarding elements can be used to read parts of the above filelist into memory.:

SAC> READ S*
   STA01E STA01N STA01Z STA02E STA02N STA02Z STA03Z
SAC> READ *Z
   STA01Z STA02Z STA03Z
SAC> READ ???
   ABC DEF
SAC> READ STA01[Z,N,E]
   STA01Z STA01N STA01E
SAC> READ *[Z,N,E]
   STA01Z STA02Z STA03Z STA01N STA02N STA01E STA02E
SAC> READ *1[Z,N,E] *2[ ]
   STA01Z STA01N STA01E STA02Z STA02N STA02E

LIMITATIONS

You may have only one concatenation string in a token. This limitation will be eliminated in a future version. Several other wildcard and filename expansion options will also be added at that time.

SEE COMMANDS

READ, READALPHA, READHDR

LATEST REVISION

May 15, 1987 (Version 10.2)