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Change the extension of a filename by using rename to convert
This will change all files ending in .JPG to .jpg and will work with any file extension

Rotate a video file by 90 degrees CW

Sort files by size

scroll file one line at a time (w/only UNIX base utilities)
usage examples ls largedir |rd lynx -dump largewebsite.com |rd rd < largelogfile

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

open two files on top of each other in vim (one window, two panes)

Connect to SMTP server using STARTTLS
Allows you to connect to an SMTP server over TLS, which is useful for debugging SMTP sessions. (Much like telnet to 25/tcp). Once connected you can manually issue SMTP commands in the clear (e.g. EHLO)

Search $PATH for a command or something similar
Searches your $PATH for whatever you substitute for bash, though not sure if this will work if you substitute a different shell for bash!

Convert seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

concat multiple videos into one (and add an audio track)
This is an extract from a larger script which formats the video for DVD. The videos I use have no audio track so I need to add one. Tweak as you like...


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