Linux and UNIX Man Pages

Test Your Knowledge in Computers #914
Difficulty: Medium
In bash, grep -v -e '^[[:space:]]*$' file.txt will filter all the blank lines from file.txt and save the results in a file called file.txt.
True or False?
Linux & Unix Commands - Search Man Pages

getenv(3c) [opensolaris man page]

getenv(3C)						   Standard C Library Functions 						getenv(3C)

getenv - return value for environment name SYNOPSIS
#include <stdlib.h> char *getenv(const char *name); DESCRIPTION
The getenv() function searches the environment list (see environ(5)) for a string of the form name=value and, if the string is present, returns a pointer to the value in the current environment. RETURN VALUES
If successful, getenv() returns a pointer to the value in the current environment; otherwise, it returns a null pointer. USAGE
The getenv() function can be safely called from a multithreaded application. Care must be exercised when using both getenv() and putenv(3C) in a multithreaded application. These functions examine and modify the environment list, which is shared by all threads in an application. The system prevents the list from being accessed simultaneously by two different threads. It does not, however, prevent two threads from successively accessing the environment list using getenv() or putenv(3C). ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ |MT-Level |Safe | +-----------------------------+-----------------------------+ SEE ALSO
exec(2), putenv(3C), attributes(5), environ(5), standards(5) SunOS 5.11 24 Jul 2002 getenv(3C)

Featured Tech Videos