curl command with flag -vvv usage-CodePudding

I saw some curl command used as following:

curl https://example.com -vvv

the -v flags is: -v, --verbose Make the operation more talkative

how the -vvv is used?

thanks!

CodePudding user response：

In some programs, -vv or -vvv are used to increase the verbosity of the output (print deeper information). In curl however it doesn't make sense, it only has 1 level of verbosity which is -v. So -vv, -vvv or even -vvvv would print the same information in curl.

CodePudding user response：

It doesn't do anything different than one -v. You just turn on verbose logging multiple times, but turning it on once would already do.

Compare the output of 1 vs 3 -vs:

curl -v web.de >1 2>&1
curl -vvv web.de >1 2>&1
diff 1 3
3,4c3,4
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0*   Trying 82.165.229.138:80...
< * Connected to web.de (82.165.229.138) port 80 (#0)
---
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0*   Trying 82.165.229.83:80...
> * Connected to web.de (82.165.229.83) port 80 (#0)
12c12
< < Date: Thu, 03 Nov 2022 15:43:22 GMT
---
> < Date: Thu, 03 Nov 2022 15:43:17 GMT
19c19
100   223  100   223    0     0    819      0 --:--:-- --:--:-- --:--:--   851
---
100   223  100   223    0     0    837      0 --:--:-- --:--:-- --:--:--   867

Naturally, time stamps are different, and the load balancer may connect you to a different server, but that's it.

Other programs like ssh increase the log level for each -v. This is usually mentioned in the man pages.

CodePudding user response：

Quoting the curl man page:

-v, --verbose

...

Providing --verbose multiple times has no extra effect.
Disable it again with --no-verbose.

So it does nothing since CURL does not have a more-verbose option.