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split large video file
i have a large video file, 500+ MB, so i cant upload it to flickr, so to reduce the size i split it into 2 files. the command shows the splitting for the first file, from 0-4 minutes. ss is start time and t is duration (how long you want the output file to be). credit goes to philc: http://ubuntuforums.org/showthread.php?t=480343 NOTE: when i made the second half of the video, i got a *lot* of lines like this: frame= 0 fps= 0 q=0.0 size= 0kB time=10000000000.00 bitrate= 0.0kbit just be patient, it is working =)

Print number of mb of free ram
This will show the amount of physical RAM that is left unused by the system.

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

Share a file quickly using a python web server
Raise your hand if you haven't used this at least once to share a directory quickly

backup with mysqldump a really big mysql database to a remote machine over ssh
backup big mysql db to remote machine over ssh. "--skip-opt" option is needed when you can?t allocate full database in ram.

get a rough estimate about how much disk space is used by all the currently installed debian packages
The vaule is expressed in megabytes

Huh? Where did all my precious space go ?
Sort ls output of all files in current directory in ascending order Just the 20 biggest ones: $ ls -la | sort -k 5bn | tail -n 20 A variant for the current directory tree with subdirectories and pretty columns is: $ find . -type f -print0 | xargs -0 ls -la | sort -k 5bn | column -t And finding the subdirectories consuming the most space with displayed block size 1k: $ du -sk ./* | sort -k 1bn | column -t

Fetch the Gateway Ip Address
This is to fetch the Gateway Ip Address of a machine. Use the below format to put the value in a variable if you wish to find the gateway ip in a script $GATEWAY=$(netstat -nr | awk 'BEGIN {while ($3!="0.0.0.0") getline; print $2}')

Advanced python tracing
Trace python statement execution and syscalls invoked during that simultaneously

Check if you need to run LaTeX to update the TOC
To check if the table-of-content in a LaTeX document is up-to-date, copy it to a backup before running LaTeX and compare the new .toc to the backup. If they are identical, it is updated. If not, you need to run LaTeX again.


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