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Get the size of all the directories in current directory (Sorted Human Readable)
This allows the output to be sorted from largest to smallest in human readable format.

Restart openssh-server on your Synology NAS from commandline.
The correct way to restart openssh-server on your synology nas.

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Reset hosed terminal,
stty sane resets the tty to basic usable function. The ^J is a newline -- sometimes CR/LF interpretation is broken so use the ^J explicitly.

disassemble binary shellcode
The options -b binary and -m are needed for disassembling raw machine code when it is not part of a full binary executable with proper headers.

Copy files for backup storage
Backup a whole directory copying only updated files.

Securely destroy data on given device hugely faster than /dev/urandom
This command generates a pseudo-random data stream using aes-256-ctr with a seed set by /dev/urandom. Redirect to a block device for secure data scrambling.

Find the 20 biggest directories on the current filesystem
This command will tell you the 20 biggest directories starting from your working directory and skips directories on other filesystems. Useful for resolving disk space issues.

validate the syntax of a perl-compatible regular expression
Place the regular expression you want to validate between the forward slashes in the eval block.

find all active IP addresses in a network
You send a unicast ICMP packet to each host. Many firewalls will drop that ICMP. However, in order to send the ICMP, you'll have first done an ARP request and the remote machine is unlikely to ignore that, so the computer will be in your ARP table.


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