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Synchronize date and time with a server over ssh
If you are stuck behind a firewall and want to synchronize time with another server but you do not want to port forward NTP (which uses UDP) then this command is handy. It gets the time from a server and sets the local time. It is not that accurate but I can live with a second or so drift.

check open ports without netstat or lsof

see the TIME_WAIT and ESTABLISHED nums of the network
see the TIME_WAIT and ESTABLISHED nums of the network

a find and replace within text-based files
using find's exec option instead of a for loop and using sed's -i option for inplace replacement. no need to do the file swap.

Extract ip addresses with sed
Extracts ip addressess from file using sed. Uses a tag(ip) to grep the IP lines after extracting. Must be a way to just output regex matched on sed.

Check whether laptop is running on battery or cable
1 = on ac, 0 = on bat

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

Netcat & Tar
Create a tarball on the client and send it across the network with netcat on port 1234 where its extracted on the server in the current directory.

File rotation without rename command
Rotates log files with "gz"-extension in a directory for 7 days and enumerates the number in file name. i.e.: logfile.1.gz > logfile.2.gz I needed this line due to the limitations on AIX Unix systems which do not ship with the rename command.


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