What Is Echo $$ In Linux?

What does echo $$ do?

echo $.

will return the exit status of last command.

The last command gave output 0 since the echo $v on the line previous finished without an error.

If you execute the commands.

v=4 echo $v echo $?.

What does $$ mean in shell script?

The $$ is the process id of the shell in which your script is running. For more details, see the man page for sh or bash. The man pages can be found be either using a command line “man sh”, or by searching the web for “shell manpage” https://stackoverflow.com/questions/78493/what-does-mean-in-the-shell/78529#78529.

What is $@ bash?

bash [filename] runs the commands saved in a file. $@ refers to all of a shell script’s command-line arguments. $1 , $2 , etc., refer to the first command-line argument, the second command-line argument, etc. … Letting users decide what files to process is more flexible and more consistent with built-in Unix commands.

How do I view a script in Linux?

2 AnswersUse the find command for it in your home: find ~ -name script.sh.If you didn’t find anything with the above, then use the find command for it on the whole F/S: find / -name script.sh 2>/dev/null. ( 2>/dev/null will avoid unnecessary errors to be displayed) .Launch it: //script.sh.Feb 22, 2017

How do I know my current shell?

How to check which shell am I using:ps -p $$ – Display your current shell name reliably.echo “$SHELL” – Print the shell for the current user but not necessarily the shell that is running at the movement.More items…•Mar 13, 2021

What will be the result of Echo $$ $? $! $0 command?

3 Answers. If the output of echo $0 command is -bash it means that bash was invoked as a login shell. If the output is only bash , then you are in a non-login shell. … A login shell is one whose first character of argument zero is a -, or one started with the –login option.

What is Echo $1?

$1 is the argument passed for shell script. Suppose, you run ./myscript.sh hello 123. then. $1 will be hello. $2 will be 123.

Does Alexa have a fee?

No, there’s no monthly fee charged for Amazon Alexa. All you need is a stable WiFi connection to make your Echo work. However, having an Amazon Prime account gives you various benefits of using the Echo.

How much does echo cost?

Echo Dot (3rd Gen) – Smart speaker with Alexa – CharcoalList Price:$39.99 DetailsYou Save:$10.00 (25%)1 more row

Is Alexa harmful?

You’re probably thinking, “Does it really matter where I put it as long as I can speak to Alexa from most areas in my house?” Our answer is yes. Placing your Alexa device in certain areas of your house could risk your privacy, security or even damage your Echo.

What is $$ in Linux?

$$ is the process ID (PID) of the script itself. $BASHPID is the process ID of the current instance of Bash. This is not the same as the $$ variable, but it often gives the same result. https://unix.stackexchange.com/questions/291570/what-is-in-bash/291577#291577. Share.

What’s the difference between Alexa and echo?

Alexa is specifically the name of the virtual assistant – the disembodied voice you talk to, ask questions, and bug with song requests. Amazon’s Echo is simply the name given to the physical products themselves, the speakers which house the AI Alexa. … For more information see our list of Alexa compatible devices.

Is there a monthly charge for Echo?

There is no cost per month. You purchase it and it is yours. If you have a subscription to Amazon Prime then you get free music and you can purchase items using voice command and it will charge your amazon account.

What is $0 bash?

$0 Expands to the name of the shell or shell script. This is set at shell initialization. If Bash is invoked with a file of commands (see Section 3.8 [Shell Scripts], page 39), $0 is set to the name of that file.

What is $1 in bash script?

$1 is the first command-line argument passed to the shell script. Also, know as Positional parameters. … $0 is the name of the script itself (script.sh) $1 is the first argument (filename1) $2 is the second argument (dir1)

Do you need an Amazon account to use Alexa?

You need an Amazon account to use Alexa, but you don’t need Amazon Prime. Sign in on the app. … Here you can add any number of Alexa-supported devices to your account, from smart lights to smart plugs. But we’re focused on Echo devices, so tap Amazon Echo; at the next screen, tap the Echo device you want to set up.

How much is Alexa monthly?

Is there a monthly fee associated with Alexa? November 11, 2019- I just got off the phone with Amazon since I’m trying to buy the new Echo and was informed there is a $3.99 monthly fee subscription for Alexa.

Do you have to pay a monthly fee for Alexa?

Cost of Setting up Amazon Alexa Amazon Alexa does not need a monthly subscription fee or anything of such sort. But you do need to set up the entire ecosystem, which would cost you money. At the bare minimum, you’d need Amazon Echo, the smart speaker from Amazon.