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Practical Programming in Tcl & Tk, Third Edition by Brent B. Welch

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Environment Variables

Environment variables are a collection of string-valued variables associated with each process. The process's environment variables are available through the global array env. The name of the environment variable is the index, (e.g., env(PATH)), and the array element contains the current value of the environment variable. If assignments are made to env, they result in changes to the corresponding environment variable. Environment variables are inherited by child processes, so programs run with the exec command inherit the environment of the Tcl script. The following example prints the values of environment variables.

Example 9-12 Printing environment variable values.
 proc printenv { args } { global env set maxl 0 if {[llength ...

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