Commands by roalddevries (1)

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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"

run complex remote shell cmds over ssh, without escaping quotes
It executes commands as arguments to ssh, avoiding problematic shell expansions, without the need of writing the commands in question to a temporary file, just reading them from STDIN.

Suppress output of loud commands you don't want to hear from
Suppresses all output to /dev/null. This could be expanded to check for a -l command line option to log the stderr to a file maybe -l file or -l to log to default quietly.log. I'm finding that I use it more often than one would think.

Calculate days on which Friday the 13th occurs (inspired from the work of the user justsomeguy)
Friday is the 5th day of the week, monday is the 1st. Output may be affected by locale.

grep processes list avoiding the grep itself
Trick to avoid the form: grep process | grep - v grep

List symbols from a dynamic library (.so file)
You can get what functions at which addresses are inside a dynamic link library by this tool.

One liner to kill a process when knowing only the port where the process is running
-k (kill option ) . To kill all processes accessing this port

Scan a document to PDF
Adjust the --resolution and --mode as required (if these options are available for your scanner). The size options (-x, -y, -imageheight, -imagewidth) are for US letter paper. For A4, I think the command would be: $scanimage -p --resolution 250 --mode Gray -x 210 -y 297 | pnmtops -imageheight 11.7 -imagewidth 8.3 | ps2pdf - output.pdf

ssh batch jobs: query hundreds of hosts with an ssh command
Need to query hundreds of hosts with an ssh command ? Of course you'll have setup keys on all your remote HOSTs. But in the case a key is not present this command will skip that node, proceeding on to the next. -t: Force pseudo-tty allocation. This can be used to execute arbitrary screen-based programs on a remote machine. Also prevents unwanted stty messages being sent to console -q: Quiet mode. -o "BatchMode yes" If set to yes, passphrase/password querying will be disabled. This option is useful in scripts and other batch jobs where no user is present

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


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