Question

27

What is the meaning of $$1 in bash?

rated 0 times [ 27] [ 0] / answers: 1 / hits: 5541 / 2 Years ago, wed, september 28, 2022, 11:58:24

I am actually playing with arguments and its happened. I just thought like to see what will happen if I type $$1 and I did it and got something below.

raja@raja-BONEFISH:~$ $$1

19301: command not found

What's that 19301 mean, is it telling something?

Bottom-Line: what does meaning for $$1 in bash.

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saucdisr

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4 Years ago

answered 2 Years ago tudatchful · Accepted Answer

$$ is the PID (process id) of the current process.

$$1 is the above PID followed by the literal string 1.

So it is telling you that your bash is the process with PID 1930.

But... free trick:

show() { eval echo $$1; }

show PATH

/home/romano/bin:/usr/local/bin:/bin:/usr/bin

(quite convoluted, ain't it?)

More info in TLDP.