The shell tries to interpret 08 as an octal number, as it starts with a zero. Only digits 0-7 are, however, allowed in octal, as decimal 8 is octal 010. Hence 08 is not a valid number, and that&#39;s the reason for the error.

Single brackets are kind of &quot;compatibility mode&quot; with sh, and sh does not know about octal numbers.

So, if you use single square brackets, &quot;010&quot; will be interpreted as 10, while with double square brackets, &quot;010&quot; will be interpreted as 8.

If you use single square brackets, &quot;08&quot; will be interpreted as 8, while with double square brackets, it is not a valid number and leads to an error.

You can avoid the error by using the solution described here: https://stackoverflow.com/a/12821845/1419315

    if [[ ${vara#0} -lt ${varb#0} ]]

or

    if [[ $((10#$vara)) -lt $((10#$varb)) ]]

I tried this:

    - command: ./configure chdir=/src/package/
    - command: /usr/bin/make chdir=/src/package/
    - command: /usr/bin/make install chdir=/src/package/

which works, but I was hoping for something neater.

So I tried this:

from: https://stackoverflow.com/questions/24043561/multiple-commands-in-the-same-line-for-bruker-topspin which give me back &quot;no such file or directory&quot;

    - command: ./configure;/usr/bin/make;/usr/bin/make install chdir=/src/package/

I tried this too: https://u.osu.edu/hasnan.1/2013/12/16/ansible-run-multiple-commands-using-command-module-and-with-items/

but I couldn&#39;t find the right syntax to put:

    - command: &quot;{{ item }}&quot; chdir=/src/package/
      with_items:
          ./configure
          /usr/bin/make
          /usr/bin/make install

That does not work, saying there is a quote issue.

ansible : how to pass multiple commands

I&#39;m trying to create a web app with Flask that lets a user upload a file and serve them to another user. Right now, I can upload the file to the *upload_folder* correctly. But I can&#39;t seem to find a way to let the user download it back.

I&#39;m storing the name of the filename into a database. 

I have a view serving the database objects. I can delete them too.

    @app.route(&#39;/dashboard&#39;, methods=[&#39;GET&#39;, &#39;POST&#39;])
    def dashboard():

        problemes = Probleme.query.all()

        if &#39;user&#39; not in session:
            return redirect(url_for(&#39;login&#39;))

        if request.method == &#39;POST&#39;:
            delete = Probleme.query.filter_by(id=request.form[&#39;del_button&#39;]).first()
            db.session.delete(delete)
            db.session.commit()
            return redirect(url_for(&#39;dashboard&#39;))

        return render_template(&#39;dashboard.html&#39;, problemes=problemes)


In my HTML I have:

    &lt;td&gt;&lt;a href=&quot;{{ url_for(&#39;download&#39;, filename=probleme.facture) }}&quot;&gt;Facture&lt;/a&gt;&lt;/td&gt;

and a download view :

    @app.route(&#39;/uploads/&lt;path:filename&gt;&#39;, methods=[&#39;GET&#39;, &#39;POST&#39;])
    def download(filename):
        return send_from_directory(directory=app.config[&#39;UPLOAD_FOLDER&#39;], filename=filename)

But it&#39;s returning : 

&gt; Not Found

The requested URL was not found on the server. If you entered the URL manually please check your spelling and try again.

I just want to link the filename to the object and let the user download it (For every object in the same view) 

Flask Download a File

Here my problem is to find the difference of using single bracket [ ] and double brackets [[ ]] in if statement.

    #!/bin/bash
    vara=08;
    varb=10;
    
    ## single bracket in if statment is working.
    if [ $vara -lt $varb ]; then
    echo &quot;yes&quot;;
    else
    echo &quot;no&quot;;
    fi
    
    
    ## double brackets in if statment is not working; throwing an error like below.
    ## [[: 08: value too great for base (error token is &quot;08&quot;)
    if [[ $vara -lt $varb ]]; then
    echo &quot;yes&quot;;
    else
    echo &quot;no&quot;;
    fi



Value too great for base (error token is &quot;08&quot;)

Here my problem is to find the difference of using single bracket [ ] and double brackets [[ ]] in if statement.
<pre><code class="hljs language-bash">#!/bin/bash
vara=08;
varb=10;

## single bracket in if statment is working.
if [ $vara -lt $varb ]; then
echo "yes";
else
echo "no";
fi


## double brackets in if statment is not working; throwing an error like below.
## [[: 08: value too great for base (error token is "08")
if [[ $vara -lt $varb ]]; then
echo "yes";
else
echo "no";
fi
</code></pre>

I was looking at pre-commit hook and discovered the following line because I was wondering why I always got an empy file called `1` in my directory after doing a commit.

    git status 2&amp;&gt;1 &gt; /dev/null

I believe the intent was to write the following, and I corrected it.

    git status 2&gt;&amp;1 &gt; /dev/null

However, I was curious about what the following syntax does exactly, so I looked up the man page.

    git status 2&amp;&gt;1


Here is the man page.

      Redirecting Standard Output and Standard Error
          This  construct allows both the standard output (file descriptor 1) and
          the standard error output (file descriptor 2) to be redirected  to  the
          file whose name is the expansion of word.
    
          There  are  two  formats  for  redirecting standard output and standard
          error:
    
                 &amp;&gt;word
          and
                 &gt;&amp;word
    
          Of the two forms, the first is preferred.  This is semantically equiva‐
          lent to
    
                 &gt;word 2&gt;&amp;1

However, this man page implies that the two are equivalent, which does not seem to be the case.

Can someone clarify the man page and explain exactly what is happening with this syntax?

What does &amp;&gt; do in bash?

I&#39;m trying to do a Bitcoin payment from within Python. In bash I would normally do this:

```none
bitcoin sendtoaddress &lt;bitcoin address&gt; &lt;amount&gt;
```

So for example:
    
```none
bitcoin sendtoaddress 1HoCUcbK9RbVnuaGQwiyaJGGAG6xrTPC9y 1.4214
```

If it is successful I get a transaction id as output, but if I try to transfer an amount larger than my bitcoin balance, I get the following output:

```none
error: {&quot;code&quot;:-4,&quot;message&quot;:&quot;Insufficient funds&quot;}
```

In my Python program I now try to do the payment as follows:

    import subprocess

    try:
        output = subprocess.check_output([&#39;bitcoin&#39;, &#39;sendtoaddress&#39;, address, str(amount)])
    except:
        print &quot;Unexpected error:&quot;, sys.exc_info()

If there&#39;s enough balance it works fine, but if there&#39;s not enough balance `sys.exc_info()` prints out this:

```none
(&lt;class &#39;subprocess.CalledProcessError&#39;&gt;, CalledProcessError(), &lt;traceback object at 0x7f339599ac68&gt;)
```

It doesn&#39;t include the error which I get on the command line though. So my question is; how can I get the outputted error (`{&quot;code&quot;:-4,&quot;message&quot;:&quot;Insufficient funds&quot;}`) from within Python?

How to catch exception output from Python subprocess.check_output()?

The lines in the file :

    -A INPUT -m state --state NEW -m tcp -p tcp --dport 2000 -j ACCEPT
    -A INPUT -m state --state NEW -m tcp -p tcp --dport 2001 -j ACCEPT
    -A INPUT -m state --state NEW -m tcp -p tcp --dport 2002 -j ACCEPT

to comment out let&#39;s say the line that contains

    2001

i can simply run this SED command:

    sed -i &#39;/ 2001 /s/^/#/&#39; file

but now how do i revert back ?

as in uncomment that same line ?

i tried

    sed -i &#39;/ 2001 /s/^//&#39; file

that does not work.

How to UNCOMMENT a line that contains a specific string using Sed?

I need to search a pattern in a directory and save the names of the files which contain it in an array.

Searching for pattern:

    grep -HR &quot;pattern&quot; . | cut -d: -f1

This prints me all filenames that contain &quot;pattern&quot;.

If I try:

    targets=$(grep  -HR &quot;pattern&quot; . | cut -d: -f1)
    length=${#targets[@]}
    for ((i = 0; i != length; i++)); do
  	   echo &quot;target $i: &#39;${targets[i]}&#39;&quot;
	done

This prints only one element that contains a string with all filnames.

    output: target 0: &#39;file0 file1 .. fileN&#39;

But I need:

     output: target 0: &#39;file0&#39;
     output: target 1: &#39;file1&#39;
     .....
     output: target N: &#39;fileN&#39;

How can I achieve the result without doing a boring split operation on targets?


Store grep output in an array

I want to list the public IP addresses of my EC2 instances using Bash, separated by a delimiter (space or a new-line).

I tried to pipe the output to [jq][1] with `aws ec2 describe-instances | jq`, but can&#39;t seem to isolate just the IP addresses.


  [1]: https://stedolan.github.io/jq/

Can this be done by `aws` alone, specifying arguments to `jq`, or something else entirely?

List public IP addresses of EC2 instances

Is there a way to prevent `envsubst` from substituting a `$VARIABLE`? For example, I would expect something like:

    export THIS=THAT
    echo &quot;dont substitute \\\$THIS&quot; | envsubst

and have it return

    dont substitute $THIS

but instead I get

    dont substitute \THAT

is there any escape character for doing this?

is there an escape character for envsubst?

I rooted my unlocked Galaxy S3 (SGH-T999)

Now, I&#39;m trying to run `adb root` from Windows *Command Prompt*, however, I&#39;m getting `adbd cannot run as root in production builds` error. So, the very first thing I checked was whether my phone was really rooted?

So I tried the following:

Open Command prompt

    $adb devices // lists my device
    $adb shell //goes to shell
    $su // opens a &#39;SuperSu&#39; prompt on my phone and I &#39;Grant&#39; permission
    # // Before following the rooting instructions, I was getting &#39;no su command found&#39; in the previous step. So, I believe my phone is ROOTED. **Correct me if I&#39;m wrong.**

However, when I do `adb root`, I get `adbd cannot run as root in production builds` error.
So, I thought, I might have to do some additional stuff beyond what I did above. I tried all the solutions in the following SO questions:

 - https://stackoverflow.com/questions/8761992/launch-a-script-as-root-through-adb
 - https://stackoverflow.com/questions/13089694/adb-remount-permission-denied-but-able-to-access-super-user-in-shell-android
 - https://stackoverflow.com/questions/18369144/unable-to-run-adb-root-on-a-rooted-android-phone

None of the above worked for me. All they do is give the ROOT access INSIDE of SHELL. I want `adb root` to work so that I can execute various adb commands WITHOUT going into shell.



adb shell su works but adb root does not

I am deploying a few different docker containers, mysql being the first one. I want to run scripts as soon as database is up and proceed to building other containers. The script has been failing because it was trying to run when the entrypoint script, which sets up mysql (from [this official mysql container](https://registry.hub.docker.com/_/mysql/)), was still running.

    sudo docker run --name mysql -e MYSQL_ROOT_PASSWORD=MY_ROOT_PASS -p 3306:3306 -d mysql
    [..] wait for mysql to be ready [..]
    mysql -h 127.0.0.1 -P 3306 -u root --password=MY_ROOT_PASS &lt; MY_SQL_SCRIPT.sql


Is there a way to wait for a signal of an entrypoiny mysql setup script finishing inside the docker container? Bash sleep seems like a suboptimal solution.

EDIT: Went for a bash script like this. Not the most elegant and kinda brute force but works like a charm. Maybe someone will find that useful.


    OUTPUT=&quot;Can&#39;t connect&quot;
    while [[ $OUTPUT == *&quot;Can&#39;t connect&quot;* ]]
    do
    	OUTPUT=$(mysql -h $APP_IP -P :$APP_PORT -u yyy --password=xxx &lt;       ./my_script.sql 2&gt;&amp;1)
    done



How do I know when my docker mysql container is up and mysql is ready for taking queries?

Can someone please tell me what&#39;s the correct way to set a bunch of environment variables in the fish shell?

In my .config/fish/config.fish file, I have a function to setup my environment variables like so

    function setTESTENV
          set -x BROKER_IP &#39;10.14.16.216&#39;
          set -x USERNAME &#39;foo&#39;
          set -x USERPASS &#39;bar&#39;
    end 

when I type from the command prompt `setTESTENV` and do a `env` in the command line, I don&#39;t see these information.  

Content Type	Original Author	Original Content on Stackoverflow
Question	Thaangaraj	View Question on Stackoverflow
Solution 1 - Bash	JohnB	View Answer on Stackoverflow

Value too great for base (error token is "08")

Bash Problem Overview

Bash Solutions

Solution 1 - Bash

Flask Download a File

ansible : how to pass multiple commands

Attributions