ssh-keygen accepting stdin
echo $pubkey | ssh-keygen -lf /dev/stdin/dev/stdin is not a public key file./dev/stdin is actually a unix pipe, not a regular file, so ssh-keygen fails to open the file
ssh-keygen -lf /dev/stdin <<<$key1024 92:6a:3f:5c:1f:78:...../dev/stdin refers to a regular file, created by using a bash heredoc. You can verify this:
# ls -l /dev/stdin <<<$pubkeylrwxrwxrwx 1 root root 15 Feb 11 08:07 /dev/stdin -> /proc/self/fd/0# ls -l /proc/self/fd/0 <<<$pubkeylr-x------ 1 juergen juergen 64 Apr 14 13:31 /proc/self/fd/0 -> /tmp/sh-thd-1271250023 (deleted)
Since version 7.2 (released on on 2016-02-28), this is now possible by passing - as the file name. From the release notes:
- ssh-keygen(1): allow fingerprinting from standard input, e.g.
ssh-keygen -lf -
If you want to redirect a string as stdin, use this syntax:
cmd <<< "some $STR here"If you want to redirect the output of a command as if it was a file, you do it like this:
cmd <( /bin/somecmd )And if you want to use a command as an OUTPUT file, it's more or less the same:
cmd >( /bin/othercmd )