What Does $$ Mean In Bash?

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.



What is bash symbol?

Special bash characters and their meaningSpecial bash characterMeaning## is used to comment a single line in bash script$$$$ is used to reference process id of any command or bash script$0$0 is used to get the name of the command in a bash script.$name$name will print the value of variable “name” defined in the script.18 more rows

What is $2 in bash?

$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)

What is DOS short for?

Disk Operating System. DOS is an acronym meaning “Disk Operating System”, which refers to a number of computer operating systems that are operated by using the command line. The term DOS is used to describe several very similar command-line systems, including MS-DOS and FreeDOS.

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 $?

Which Alexa model is best?

Best Alexa speakers 2021: the best Alexa-enabled smart speakersSonos One. … Audio Pro Addon C5A. … Amazon Echo Show 5. … Ultimate Ears Megablast. … Amazon Echo (4th Gen) … Amazon Echo (3rd Generation) … Amazon Echo Spot. A clock radio that also doubles as an Alexa smart speaker. … Amazon Echo Studio. A big, bold-sounding Alexa speaker with plenty going for it.More items…•Feb 18, 2021

How much does Alexa cost a month?

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.

Are Alexa and echo the same thing?

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 this symbol called?

British vs. American EnglishBritish EnglishAmerican EnglishThe ” . ” symbol is calledA full stopa periodThe ” ! ” symbol is calledan exclamation markan exclamation pointThe ” ( ) ” symbols are calledbracketsparenthesesThe ” [ ] ” symbols are calledsquare bracketsbrackets2 more rows

What is your currency mean?

Currency is a medium of exchange for goods and services. In short, it’s money, in the form of paper or coins, usually issued by a government and generally accepted at its face value as a method of payment. … In the 21st century, a new form of currency has entered the vocabulary, the virtual currency.

What does $? Mean in bash?

1. 21. Loading when this answer was accepted… $? is the last error (or success) returned: $? 1: command not found.

Is Echo better than dot?

Basically, the only difference between the two devices, other than size and cost, is sound. If you’re just looking to be introduced to Alexa, you’ll be fine with the Echo Dot. It has all the smarts of Alexa in a small speaker. … All in all, the Echo Dot is an ideal choice for most people.

Is Alexa a spying device?

Is Alexa spying on me? The truth revealed. As far as we know, Amazon isn’t using your Alexa to eavesdrop on everything you do. … However, Alexa will sometimes record you without your knowledge, because she thought you said her name.

Do I need 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.

Do I need a Prime account to use Alexa?

You need an Amazon account to use Alexa, but you don’t need Amazon Prime. … Here you can add any number of Alexa-supported devices to your account, from smart lights to smart plugs.

What does $? Mean?

was last command successful$? = was last command successful. Answer is 0 which means ‘yes’.