printenv: Print all or some environment variables
printenv prints environment variable values. Synopsis:
printenv [option] [variable]…
variables are specified,
printenv prints the value of
every environment variable. Otherwise, it prints the value of each
variable that is set, and nothing for those that are not set.
The program accepts the following option. Also see Common options.
Output a zero byte (ASCII NUL) at the end of each line, rather than a newline. This option enables other programs to parse the output even when that output would contain data with embedded newlines.
0 if all variables specified were found 1 if at least one specified variable was not found 2 if a write error occurred