Commands by crishoj (2)

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List all symbolic links in current directory
For those who don't have the symlinks command, you can use readlink. This command is not straightforward because readlink is very picky. The backslash in front of 'ls' means not to use an alias (e.g. color escape codes from an aliased 'ls' could mess up readlink), and the -1 (one) means to print the entries separated by newlines. xargs -l (the letter L) means to process each input separated by newlines as separate commands.

print DateTimeOriginal from EXIF data for all files in folder
see output from `identify -verbose` for other keywords to filter for (e.g. date:create, exif:DateTime, EXIF:ExifOffset).

Create a tar of directory structure only

Kill multiple instances of a running process

get absolute file path
Retrieve absolute path name from relative path

Quickly create simple text file from command line w/o using vi/emacs
1. Issue command 2. After angled bracket appears, enter file contents 3. When done, type "EOF"

Port Knocking!
Knock on ports to open a port to a service (ssh for example) and knock again to close the port. You have to install knockd. See example config file below. [options] logfile = /var/log/knockd.log [openSSH] sequence = 3000,4000,5000 seq_timeout = 5 command = /sbin/iptables -A INPUT -i eth0 -s %IP% -p tcp --dport 22 -j ACCEPT tcpflags = syn [closeSSH] sequence = 5000,4000,3000 seq_timeout = 5 command = /sbin/iptables -D INPUT -i eth0 -s %IP% -p tcp --dport 22 -j ACCEPT tcpflags = syn

Get AWS temporary credentials ready to export based on a MFA virtual appliance
You might want to secure your AWS operations requiring to use a MFA token. But then to use API or tools, you need to pass credentials generated with a MFA token. This commands asks you for the MFA code and retrieves these credentials using AWS Cli. To print the exports, you can use: `awk '{ print "export AWS_ACCESS_KEY_ID=\"" $1 "\"\n" "export AWS_SECRET_ACCESS_KEY=\"" $2 "\"\n" "export AWS_SESSION_TOKEN=\"" $3 "\"" }'` You must adapt the command line to include: * $MFA_IDis ARN of the virtual MFA or serial number of the physical one * TTL for the credentials

Debug SSH at the Maximum Verbosity Level
When debugging an ssh connection either to optimize your settings ie compression, ciphers, or more commonly for debugging an issue connecting, this alias comes in real handy as it's not easy to remember the '-o LogLevel=DEBUG3' argument, which adds a boost of debugging info not available with -vvv alone. Especially useful are the FD info, and the setup negotiation to create a cleaner, faster connection.

monitor what processes are waiting for IO interrupts

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