NAME

ckstr − display a prompt; verify and return a string answer

SYNOPSIS

ckstr [ -Q ] [ -W width ] [ [ -r regexp ] [ -r regexp ] . . . ] [ -l length ]
[ -d default ] [ -h help ] [ -e error ] [ -p prompt ] [ -k pid [ -s signal ] ]

errstr [ -W width ] [ -e error ] [ [ -r regexp ] [ -r regexp ] . . . ] [ -l length ]

helpstr [ -W width ] [ -h help ] [ [ -r regexp ] [ -r regexp ] . . . ] [ -l length ]

valstr input [ [ -r regexp ] [ -r regexp ] . . . ] [ -l length ]

DESCRIPTION

ckstr prompts a user and validates the response.  It defines, among other things, a prompt message whose response should be a string, text for help and error messages, and a default value (which is returned if the user responds with a RETURN). 

The answer returned from this command must match the defined regular expression and be no longer than the length specified.  If no regular expression is given, valid input must be a string with a length less than or equal to the length defined with no internal, leading or trailing white space.  If no length is defined, the length is not checked.  Either a regular expression or a length must be given with the command. 

All messages are limited in length to 70 characters and are formatted automatically.  Any white space used in the definition (including newline) is stripped.  The −W option cancels the automatic formatting.  When a tilde is placed at the beginning or end of a message definition, the default text is inserted at that point, allowing both custom text and the default text to be displayed. 

If the prompt, help or error message is not defined, the default message (as defined under NOTES) is displayed. 

Three visual tool modules are linked to the ckstr command.  They are errstr (which formats and displays an error message), helpstr (which formats and displays a help message), and valstr (which validates a response).  These modules should be used in conjunction with FACE objects.  In this instance, the FACE object defines the prompt. 

The options and arguments for this command are:

−Q Do not allow quit as a valid response. 

−W Use width as the line length for prompt, help, and error messages. 

−r Validate the input against regular expression regexp.  May include white space.  If multiple expressions are defined, the answer need match only one of them. 

−l The maximum length of the input is length. 

−d The default value is default.  The default is not validated and so does not have to meet any criteria. 

−h The help message is help. 

−e The error message is error. 

−p The prompt message is prompt. 

−k Send process ID pid a signal if the user chooses to abort. 

−s When quit is chosen, send signal to the process whose pid is specified by the −k option.  If no signal is specified, use SIGTERM. 

input Input to be verified against format length and/or regular expression criteria. 

EXIT CODES

0 = Successful execution
1 = EOF on input
2 = Usage error
3 = User termination (quit)

NOTES

The default prompt for ckstr is:

Enter an appropriate value [?,q]

The default error message is dependent upon the type of validation involved.  The user is told either that the length or the pattern matching failed. 

The default help message is also dependent upon the type of validation involved.  If a regular expression has been defined, the message is:

Please enter a string which matches the following pattern:
regexp

Other messages define the length requirement and the definition of a string. 

When the quit option is chosen (and allowed), q is returned along with the return code 3.  The valstr module does not produce any output.  It returns zero for success and non-zero for failure. 

Unless a “q” for “quit” is disabled by the -Q option, a single “q” to the following

ckstr -rq

is treated as a “quit” and not as a pattern match. 

  —  Essential Utilities