01-27-2017
I'm not sure on using backquotes is wrong per se.
$(command) are both `command` are both currently valid syntax and in standards.
Exception being, that actually backquotes should work on even the oldest shells (and new ones), while other form might not.
If i'm not mistaken backquotes are still the lowest common denominator for command substitution if you wish your scripts to work anywhere without touching
But today it's hard to find such shells as defaults or even existing on operating systems.
So i tend to write scripts using $(command) method, as well as promote such way.
Regards
Peasant.
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putenv(3) Library Functions Manual putenv(3)
NAME
putenv - Sets an environment variable
LIBRARY
Standard C Library (libc.so, libc.a)
SYNOPSIS
#include <stdlib.h>
int putenv(
const char *string);
STANDARDS
Interfaces documented on this reference page conform to industry standards as follows:
putenv(): XPG4, XPG4-UNIX
Refer to the standards(5) reference page for more information about industry standards and associated tags.
PARAMETERS
Points to a name=value string.
DESCRIPTION
The putenv() function sets the value of an environment variable by altering an existing variable or by creating a new one. The new envi-
ronment variable remains in effect even after the program setting it is exited.
The string parameter points to a string of the form "name=value", where name is the environment variable and value is the new value for it.
NOTES
The putenv() function manipulates the environ external variable, and it can be used in conjunction with the getenv() function. However, the
third parameter to the main function (the environment pointer) is not changed.
The putenv() function uses the malloc() function to enlarge the environment.
A potential error is to call putenv() with an automatic variable as the argument and then exit the calling function while string is still
part of the environment.
RETURN VALUES
Upon successful completion, a value of 0 (zero) is returned. If the malloc() function is unable to obtain sufficient space to expand the
environment, the putenv() function returns a nonzero value.
RELATED INFORMATION
Functions: clearenv(3), exec(2), getenv(3), malloc(3)
Standards: standards(5) delim off
putenv(3)