Commands by fivestones (2)

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remove empty lines in place with backup
Modify file in place to remove empty lines and create a backup of the original with the extension .bak

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.

Check if you work on a virtual/physical machine in Linux
Command used to know if we are working on a virtual or physical machine. This command will use the dmidecode utility to retrieve hardware information of your computer via the BIOS. Run this command as root or with sudo.

Generate pretty secure random passwords
These are my favourite switches on pwgen: -B Don't include ambiguous characters in the password -n Include at least one number in the password -y Include at least one special symbol in the password -c Include at least one capital letter in the password It just works! Add a number to set password length, add another to set how many password to output. Example: pwgen -Bnyc 12 20 this will output 20 password of 12 chars length.

Ultimate current directory usage command
An NCurses version of the famous old 'du' unix command

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"

Grab the top 5 CLFUContest one-liners

Mount a .iso file in UNIX/Linux
"-o loop" lets you use a file as a block device

Control ssh connection
SSH can be controlled trough an ~ escape sequence. Example, to terminate the current ssh connection, type a newline, then the ~ character, and last a . character. This is useful eg when an ssh connection hangs after you reboot a machine and the connection hangs.

Detect if we are running on a VMware virtual machine
If you run this command on a VMWare Virtual Machine, it will return the string "VMware Virtual Platform". If you run it on a physical machine, it will return nothing. Useful for having a script determine if it's running on a VM or not. Of course, you must have dmidecode installed for this to work. Try it this way in a script: ISVM=$(dmidecode | awk '/VMware Virtual Platform/ {print $3,$4,$5}') Then test if $ISVM has text in it, or is blank.


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