GNU coreutils : backup option related to cp command

$cd  test-folder/
$>1
$>2
$>3
$ls
1  2  3
$cd ..
$>1
$>2
$cp -b 1 test-folder/
$cd test-folder/
$ls
1  1~  2  3
$cd ..
$export SIMPLE_BACKUP_SUFFIX=bc
$cp -b 2 test-folder/
$cd test-folder/
$ls
1  1~  2  2bc  3
$cd ..
$export SIMPLE_BACKUP_SUFFIX=.bc
$cp -b 2 test-folder/
$cd test-folder/
$ls
1  1~  2  2bc  2.bc  3
$


GNU bash exit codes with special meanings

$printenv > /dev/null 
$echo $?
0
$printenv /dev/null 
$echo $?
1
$/dev/null
bash: /dev/null: Permission denied
$echo $?
126
$nocommand
bash: nocommand: command not found...

$
$echo $?
127
$

http://www.tldp.org/LDP/abs/html/exitcodes.html
GNU coreutils with (delimit the option list) feature

$echo "hello" >  --test
$cat --test
cat: unrecognized option '--test'
Try 'cat --help' for more information.
$cat -- --test
hello
$

string and integer variable operation using Javascript

<!DOCTYPE html> 
 
<html lang="en"> 
<head> 
    <title>Chapter 2, Example 1</title> 
</head> 
<body> 
    <script> 
        var myFirstVariable; 
 
        myFirstVariable = "Hello"; 
        alert(myFirstVariable); 
 
        myFirstVariable = 54321; 
        alert(myFirstVariable); 
    </script> 
</body> 
</html>

Key source : Beginning JavaScript, 5th Edition (wrox)

Adding text to html element using JavaScript


<!DOCTYPE html>

<html lang="en">
<head>
<meta charset="utf-8" />
<title>Chapter 1, Example 3</title>
</head>
<body>
<code id="results"></code>
<script>
document.getElementById("results").innerHTML = "Hello World!";
</script>
</body>
</html>

Key source : Beginning JavaScript, 5th Edition (wrox)

settings with color and alert messages using Javascript


<!DOCTYPE html>

<html lang="en">
<head>
<meta charset="utf-8" />
<title>Chapter 1, Example 2</title>
</head>
<body bgcolor="white">
<p>Paragraph 1</p>
<script>
// script block 1
alert("First Script Block");
</script>
<p>Paragraph 2</p>
<script>
// script block 2
document.bgColor = "red";
alert("Second Script Block");
</script>
<p>Paragraph 3</p>
</body>
</html>

 

Key source : Beginning JavaScript, 5th Edition (wrox)

setting up background color using JavaScript


<!DOCTYPE html>

<html lang="en">
<head>
<meta charset="utf-8" />
<title>Chapter 1, Example 1</title>
</head>
<body bgcolor="white">
<p>Paragraph 1</p>
<script>
document.bgColor = "blue";
</script>
</body>
</html>

Key source : Beginning JavaScript, 5th Edition (wrox)