If the variable is: `FOO=&quot;qwertzuiopasdfghjklyxcvbnm&quot;`

then

     echo ${FOO:0:10}

will give the first 10 characters.

Use the `head` command.

    echo $FOO | head -c 10
    =&gt; qwertzuiop


I would like my webpage&#39;s *viewport width* to equal *device-width* as long as *device-width* &gt; 450px, or 450px otherwise (my layout dynamically scales, but doesn&#39;t look good below 450px wide).

The following two meta tags work well on tablets, where the device-width &gt; 450px:

    &lt;!-- uses device width --&gt;
    &lt;meta name=&quot;viewport&quot; content=&quot;width=device-width&quot; /&gt;

    &lt;!-- use of initial-scale means width param is treated as min-width --&gt;
    &lt;meta name=&quot;viewport&quot; content=&quot;width=450, initial-scale=1.0&quot; /&gt;
		
however, on phones (where e.g. device-width=320px) the former is too thin for the content; and the latter causes the browser to zoom in, so the user has to manually zoom out to see the content.

Alternatively, this meta tag works well on phones

    &lt;meta name=&quot;viewport&quot; content=&quot;width=450&quot; /&gt;
	
but doesn&#39;t take advantage of the extra width available on tablets.

Any help/ideas would be really appreciated (and if it makes a difference, I&#39;m using GWT).

Achieving min-width with viewport meta tag

Suppose I have the next text :

&gt; Hello stackOverflow

And I wish to set the second word to be both [RelativeSizeSpan][1] (to set a relative font size) and [TextAppearanceSpan][2] (to set the color of the text) , how do I merge them both ?

All I know is that I can choose one of them , using the next code for example :

    final SpannableString textToShow = new SpannableString(&quot;Hello stackOverflow&quot;);
    textToShow.setSpan(new RelativeSizeSpan(1.5f), textToShow.length() - &quot;stackOverflow&quot;.length(),textToShow.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
    textView.setText(textToShow);

But I need to also set the color , or even add other features from other spanning classes ...

What can I do ?


  [1]: http://developer.android.com/reference/android/text/style/RelativeSizeSpan.html
  [2]: http://developer.android.com/reference/android/text/style/TextAppearanceSpan.html

How to set multiple spans on a TextView&#39;s text on the same partial text?

How to retrieve the first 10 characters of a variable with Bash?

    FOO=&quot;qwertzuiopasdfghjklyxcvbnm&quot;

I need to get `qwertzuiop`.

How to retrieve the first n characters of a variable in Bash?

How to retrieve the first 10 characters of a variable with Bash?
<pre><code class="hljs language-ini">FOO="qwertzuiopasdfghjklyxcvbnm"
</code></pre>
I need to get <code>qwertzuiop</code>.

I want to rename all files and directories that contain the word &quot;special&quot; to &quot;regular&quot;. It should maintain case sensitivity so &quot;Special&quot; won&#39;t become &quot;regular&quot;.

How can i do this in bash recursively? 

Rename files and directories recursively under ubuntu /bash

I know some very basic commands in Linux and am trying to write some scripts. I have written a function which evaluates the sum of last 2-digits in a 5-digit number. The function should concatenate this resultant sum in between the last 2-digits and return it. The reason I want to return this value is because I will be using this value in the other function. 

Ex: if I have 12345, then my function will calculate 4+5 and return 495.

    #!/bin/bash
    
    set -x
    echo &quot;enter: &quot;
            read input
    
    function password_formula
    {
            length=${#input}
            last_two=${input:length-2:length}
            first=`echo $last_two| sed -e &#39;s/$.$/\1 /g&#39;|awk &#39;{print $2}&#39;`
            second=`echo $last_two| sed -e &#39;s/$.$/\1 /g&#39;|awk &#39;{print $1}&#39;`
            let sum=$first+$second
            sum_len=${#sum}
            echo $second
            echo $sum
    
            if [ $sum -gt 9 ]
            then
                   sum=${sum:1}
            fi
    
            value=$second$sum$first
            return $value
    }
    result=$(password_formula)
    echo $result

I am trying to echo and see the result but I am getting the output as shown below. 

    -bash-3.2$ ./file2.sh 
    +++ password_formula
    +++ echo &#39;enter: &#39;
    +++ read input
    12385
    +++ length=8
    +++ last_two=85
    ++++ echo 85
    ++++ sed -e &#39;s/$.$/\1 /g&#39;
    ++++ awk &#39;{print $2}&#39;
    +++ first=5
    ++++ echo 85
    ++++ sed -e &#39;s/$.$/\1 /g&#39;
    ++++ awk &#39;{print $1}&#39;
    +++ second=8
    +++ let sum=5+8
    +++ sum_len=2
    +++ echo 5
    +++ echo 8
    +++ echo 13
    +++ &#39;[&#39; 13 -gt 9 &#39;]&#39;
    +++ sum=3
    +++ value=835
    +++ return 835
    ++ result=&#39;enter: 
    5
    8
    13&#39;
    ++ echo enter: 5 8 13
    enter: 5 8 13


I also tried to print the result as:

    password_formula
    RESULT=$?
    echo $RESULT

But that is giving some unknown value: 

    ++ RESULT=67
    ++ echo 67
    67


How can I properly store the correct value and print (to double check) on the screen? 

Thanks in advance.






In bash, how to store a return value in a variable?

I have a backup script on my server which does cron jobs of backups, and sends me a summary of  files backed up, including the size of the new backup file. As part of the script, I&#39;d like to divide the final size of the file by (1024^3) to get the file size in GB, from the file size in bytes. 

Since bash does not have floating point calculation, I am trying to use pipes to bc to get the result, however I&#39;m getting stumped on basic examples.

I tried to get the value of Pi to a scale, however,

even though the following works:

	~ #bc -l
	bc 1.06.95
	Copyright 1991-1994, 1997, 1998, 2000, 2004, 2006 Free Software Foundation, Inc.
	This is free software with ABSOLUTELY NO WARRANTY.
	For details type `warranty&#39;.
	4/3
	1.33333333333333333333
	22/7
	3.14285714285714285714
	q
	0
	quit

A non interactive version does not work:

	#echo $(( 22/7 )) | bc
	3
This works:

	#echo &#39;22/7&#39; | bc -l
	3.14285714285714285714

But I need to use variables. So it doesnt help that the following does not work:

	#a=22 ; b=7
	#echo $(( a/b )) | bc -l
	3

I&#39;m obviously missing something in the syntax for using variables in Bash, and could use with some &#39;pointers&#39; on what I&#39;ve misunderstood.

As DigitalRoss said, I can use the following:

	#echo $a / $b | bc -l
	3.14285714285714285714

However I cant use complex expressions like:

	#echo $a / (( $b-34 )) | bc -l
	-bash: syntax error near unexpected token `(&#39;
	#echo $a / (( b-34 )) | bc -l
	-bash: syntax error near unexpected token `(&#39;
	#echo $a / (( b-34 )) | bc -l
	-bash: syntax error near unexpected token `(&#39;

Can someone give me a working correct syntax for getting floating point results with complicated arithmetic expresssions?

Floating point results in Bash integer division

I have something in `bash` like

    myArray=(&#39;red&#39; &#39;orange&#39; &#39;green&#39;)

And I would like to do something like

    echo ${myArray[&#39;green&#39;]}

Which in this case would output `2`. Is this achievable?

Get the index of a value in a Bash array

The following command attempts to enumerate all `*.txt` files in the current directory and process them one by one:

    for line in &quot;find . -iname &#39;*.txt&#39;&quot;; do 
         echo $line
         ls -l $line; 
    done


Why do I get the following error?:

    ls: invalid option -- &#39;e&#39;
    Try `ls --help&#39; for more information.



Content Type	Original Author	Original Content on Stackoverflow
Question	user2093552	View Question on Stackoverflow
Solution 1 - Bash	P.P	View Answer on Stackoverflow
Solution 2 - Bash	pje	View Answer on Stackoverflow

How to retrieve the first n characters of a variable in Bash?

Bash Problem Overview

Bash Solutions

Solution 1 - Bash

Solution 2 - Bash

How to set multiple spans on a TextView's text on the same partial text?

Achieving min-width with viewport meta tag

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