standard error to standard input.

standard input to standard error.

standard output to standard error.

standard error to standard output.

standard output to standard input.

It must be sent by any SSH client in addition to a user key in order to identify the client's host.

It provides the server's identity information to connecting SSH clients.

It is the root key by which all user SSH keys must be signed.

It authenticates any user that logs into a remote machine from the key's host.

It is used by system services like cron, syslog or a backup job to automatically connect to remote hosts.

2001:db8:3241::1

2001::db8:4581::1

2001:db8:0g41::1

2001%db8%9990%%1

2001.db8.819f..1

It is a plain text file containing a string such as Europe/Berlin.

It is created and maintained by the NTP service based on the geolocation of the system's IP address.

It is a symlink to /sys/device/clock/ltime and always contains the current local time.

It is either a symlink to or a copy of a timezone information file such as /usr/share/zoneinfo/Europe/Berlin.

mydate="$(date)"

mydate="exec date"

mydate="$((date))"

mydate="date"

mydate="${date}"

2 > & 1 > filename

> filename 2 > & 1

1 > & 2 > filename

> > filename

1 & 2 > filename

3

4

5

6

7

A B

A B C

A C

B C

C B A

chmod +s /tmp

chmod +t /tmp

chmod 1775 /tmp

chmod 4775 /tmp

chmod 2775 /tmp