Linux Ask! is a Q & A web site specific for Linux related questions. Questions are collected, answered and audited by experienced Linux users.
Print to standard output in different scripting languages
Answer:
To print a string of "Hello World" to the standard output in different scripting languages
1. Perl
print "Hello, World!";
2. Python
print('Hello, World!')
3. PHP
echo "Hello, World!";
4. Ruby
puts "Hello, World!"
Enable Perl strict mode to restrict unsafe constructs
Answer:
In Perl, you can enforce using the strict mode to reduce the chance of nasty error, e.g.
$foo = 'bar';
print $foo;If you run the above problem, it is completely valid.
# perl test.pl
bar
However, if you use the strict pragma
use strict;
$foo = 'bar';
print $foo;And run the program again..
# perl test.pl
Global symbol "$foo" requires explicit package name at test.pl line 3.
Global symbol "$foo" requires explicit package name at test.pl line 4.
Execution of test.pl aborted due to compilation errors.Since the $foo is not declared before the first use, so the compilation stopped. In modern Perl developements, it is recommended to alwasys use the strict pragma in order to write a better and maintainable program.
To fix the problem, you need to use the my keyword, e.g.
use strict;
my $foo = 'bar';
print $foo;And run the program again. (Thanks Jeroen for the suggestion)
Show the current privileges of a MySQL user
Answer:
To show the current privileges of a MySQL user, you can use the SHOW GRANTS statement
E.g.
mysql> SHOW GRANTS;
+----------------------------------------------------------------------------------------------------------------------------------------+
| Grants for root@localhost |
+----------------------------------------------------------------------------------------------------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' IDENTIFIED BY PASSWORD '*****************************************' WITH GRANT OPTION |
+----------------------------------------------------------------------------------------------------------------------------------------+How to install a NodeJS module using npm globally
Answer:
By default, node modules installed using simple node install will be installed under the folder ./node_modules. In order to install the modules globally, try
# sudo npm install express -gThe above command install the express module as global module.
Install the node package manager (npm)
Answer:
npm is a package manager for node.js, to install it under Linux, just a single command:
# curl http://npmjs.org/install.sh | sudo sh
