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Find files with lines that do not match a pattern
This one would be much faster, as it's only one executed command.

Print just line 4 from a textfile
Prints the 4th line and then quits. (Credit goes to flatcap in comments: http://www.commandlinefu.com/commands/view/6031/print-just-line-4-from-a-textfile#comment.)

Calculates the date 2 weeks ago from Saturday the specified format.
Good for automating reports that need to run from between two dates.

Null a file with sudo

Outgoing IP of server
Faster than the curl/wget-approaches.

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

List only executables installed by a debian package
I wanted to view only executables installed by a package. This seemed to work. There's got to be easier way, please share. Note: (1) Replace iptables with the package name of your interest (2) The command will trash any existing environment variable named 'lst' (3) Instead if you are interested in viewing just .ko or .so files installed by this package, then that would be easy: $ dpkg -L iptables | grep "\.[sk]o$"

Create a mirror of a local folder, on a remote server
Create a exact mirror of the local folder "/root/files", on remote server 'remote_server' using SSH command (listening on port 22) (all files & folders on destination server/folder will be deleted)

Find files with the same names in several directories.
cat file1 file2 file3|sort|uniq -d finds the same lines in several files, especially in files with lists of files.

See entire packet payload using tcpdump.


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