OSF DCE Administration Guide--Core Components

OSF DCE Administration Guide—Core Components
• Using lists to sort, find, and reuse information
• Using arithmetic functions in commands and task scripts
• Conditionalizing and controlling your script with if statements and loops
• Executing scripts associated with character patterns by using the case command
• Synthesizing commands by using eval
• Importing operations with source
• Creating new dcecp commands with proc
• Using error and exception information
• Handling strings
• Working with files
• Spawning subprocesses
2.2 Variable Substitution
Like other programming languages, dcecp provides shorthand ways to express and use
values. Variable substitution is one shorthand method that lets you represent a value—
say, the name of an object in a CDS directory—as a variable.
Use the set command to establish a value for a variable. For readability, a variable name
can consist of any combination of letters, numbers, and _ (underscore) characters. Use ""
(quotes) or \ (backslash) to include spaces in variable names (although this is not usually
recommended) or values. All of the following examples use valid variable names:
seta$i
set CDS_clearinghouse_name cambridge_ch
set DCE_user_1 "William Rosenberry"
The following example sets variable a to have a value of 7. The second use of the set a
command without a value causes dcecp to display the current value of the variable:
dcecp> set a 7
7
dcecp> set a
7
Once you have established a value for a variable using the dcecp set command, the
variable can be subsequently used elsewhere in your script or interactive command. The
DCE control program uses the $ (dollar sign) to trigger insertion of the current value into
the command word. A simple example is
dcecp> set a 7
7
dcecp> expr $a+2
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