what does the code mean: if [$? -eq 0] mean?

Question

I'm in the process of generating an automatic installation script. I want to test if the tool already is already installed in the system, I found this line :

  if [$? -eq 0]

but I did not understand what it means... is it complete or not?

thank you in advance.

It's an error, because you didn't put spaces around the `[` and `]`. — chepner, Feb 02 '21 at 13:18

score 0 · Accepted Answer · answered Feb 02 '21 at 13:05

$? shows the exit code of the previous process, If everything is ok then the exit code is equals to 0, 1 for the processes having minor problems/warnings and 2 or more than 2 means fatal errors were caused and during termination of the process

so -eq here means equals

so basically this line of code is checking if the exit code of previous process was 0 or not

what does the code mean: if [$? -eq 0] mean?

1 Answers1