function interval(func, wait, times){
    var interv = function(w, t){
        return function(){
            if(typeof t === "undefined" || t-- > 0){
                setTimeout(interv, w);
                try{
                    func.call(null);
                }
                catch(e){
                    t = 0;
                    throw e.toString();
                }
            }
        };
    }(wait, times);

    setTimeout(interv, wait);
}

The interval function has an internal function called interv which gets invoked automatically via setTimeout, within interv is a closure that checks the the repetition times, invokes the callback and invokes interv again via setTimeout. In case an exception bubbles up from the callback call the interval calling will stop and the exception will be thrown.

This pattern does not guarantee execution on a fixed interval of course, yet it does guarantee that the previous interval has completed before recursing, which I think is much more important.

Usage

interval(function(){
    // Code block goes here
}, 1000, 10);

So to execute a piece of code 5 times with an interval or 10 seconds between each you would do something like this:

thecodeship

Mission

Many functional programming learning resources will teach you to write functional code, but it's often highly indirect, deeply abstracted, requires understanding complex relationships between custom library calls, and doesn't represent the reality of how people actually write JavaScript.

The goal of this workshop is to create realistic problems that can be solved using terse, vanilla, idiomatic JavaScript.

functional-javascript-workshop

Bzip2 is used to compress a file in order to reduce disk space, it is quite popular in Linux and UNIX operating systems for this reason. Bzip2 has been around since the late 1990s and is still widely used today. It may be preferable over gzip as it can produce smaller compressed files, at the cost of additional memory and processing time.

Compress a single file

bzip2 file.txt

This will compress file.txt and create file.txt.bz2, note that this will remove the original file.txt file.

Compress multiple files at once

zip2 file1.txt file2.txt file3.txt

This will compress all files specified in the command, note again that this will remove the original files specified by turning file1.txt, file2.txt and file3.txt into file1.txt.bz2, file2.txt.bz2 and file3.txt.bz2

Compress a single file and keep the original

bzip2 -c file.txt > file.txt.bz

You can instead keep the original file and create a compressed copy.
The -c flag outputs the compressed copy of file.txt to stdout, this is then sent to file.txt.bz2, keeping the original file.txt file in place.

The version of bzip2 which is currently the latest available as of this writing also has the -k option which keeps the original file, so alternatively you could also run the below command to get the same result.

bzip2 -k file.txt

Decompress a bzip2 compressed file

bzip2 -d file.txt.bz2

# OR

bunzip2 file.txt.bz2

To reverse the compression process and get the original file back that you have compressed, you can use the bzip2 command itself or bunzip2 which is also part of the bzip2 package.

Both of these commands will produce the same result, decompressing file.txt.bz2 to file.txt, removing the compressed file.txt.bz2 file.

Similar to example 3, it is possible to decompress a file and keep the original .bz2 file as below.

bunzip2 -c file.txt.bz2 > file.txt

# OR

bunzip2 -k file.txt.bz2

List compression information

[root@centos ~]# bzip2 -v linux-3.18.19.tar
  linux-3.18.19.tar:  6.015:1,  1.330 bits/byte, 83.37% saved, 580761600 in, 96552670 out.

With the -v or –verbose flag we can see useful information regarding the compression ratio of a file, which shows us how much disk space our compression is saving. Additional ‘v’ flags can be added for more in depth information.

full-guide

You can issue the following query from the command line:

mysql -uUSER -p -e 'SHOW VARIABLES WHERE Variable_Name LIKE "%dir"'

Output (on Linux):

+---------------------------+----------------------------+
| Variable_name             | Value                      |
+---------------------------+----------------------------+
| basedir                   | /usr                       |
| character_sets_dir        | /usr/share/mysql/charsets/ |
| datadir                   | /var/lib/mysql/            |
| innodb_data_home_dir      |                            |
| innodb_log_group_home_dir | ./                         |
| lc_messages_dir           | /usr/share/mysql/          |
| plugin_dir                | /usr/lib/mysql/plugin/     |
| slave_load_tmpdir         | /tmp                       |
| tmpdir                    | /tmp                       |
+---------------------------+----------------------------+

stackoverflow

Run the below command on terminal to see the contents of a tar.gz file without extracting it:

tar -tf filename.tar.gz

askubuntu