Commands by poole (1)

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diff the outputs of two programs
I've been looking for this for a long time. Does anybody know how to do this in dash (POSIX shell)? An alternative version might be: $ exiftool img_1.jpg | diff -

export iPad App list to txt file
This will generate the same output without changing the current directory, and filepath will be relative to the current directory. Note: it will (still) fail if your iTunes library is in a non-standard location.

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" }

Make window transparent (50% opacity) in Gnome shell
Click window to change its opacity. Source: https://unix.stackexchange.com/a/494289

Limit memory usage per script/program
When I'm testing some scripts or programs, they end up using more memory than anticipated. In that case, computer nearly halts due to swap space usage, and sometimes I have to press Magic SysRq+REISUB to reboot. So, I was looking for a way to limit memory usage per script and found out that ulimit can limit memory. If you run it this way: $ $ ulimit -v 1000000 . $ $ scriptname Then the new memory limit will be valid for that shell. I think changing the limit within a subshell is much more flexible and it won't interfere with your current shell ulimit settings. note: -v 1000000 corresponds to approximately 1GB of RAM

check open ports without netstat or lsof

Configure second monitor to sit to the right of laptop
You'll need to make sure your xorg.conf permits a virtual screen size this big. If it doesn't then xrandr should return a suitable error message that tells you the required size.

Encrypted chat with netcat and openssl (one-liner)
client$ while true; do read -n30 ui; echo $ui |openssl enc -aes-256-ctr -a -k PaSSw ; done | nc localhost 8877 | while read so; do decoded_so=`echo "$so"| openssl enc -d -a -aes-256-ctr -k PaSSw`; echo -e "Incoming: $decoded_so"; done This will establish a simple encrypted chat with AES-256-CTR using netcat and openssl only. More info here https://nixaid.com/encrypted-chat-with-netcat/

Search specified $TEXT1 and Replace that by specified arg ($TEXT2)

Prints the latest modified files in a directory tree recursively
Sorts by latest modified files by looking to current directory and all subdirectories


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