Commands by Coderjoe (1)

What's this? is the place to record those command-line gems that you return to again and again. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

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Convert CSV to JSON
Replace 'csv_file.csv' with your filename.

Bash scripts encryption and passphrase-protection
This function will encrypt a bash script and will only execute it after providing the passphrase. Requires mcrypt to be installed on the system. $ cat hello #!/bin/bash case "$1" in ""|-h) echo "This is the fantastic Hello World. Try this:" $(basename $0) "[entity]" ;; moon) echo Good night. ;; sun) echo Good morning. ;; world) echo "Hello, world!" ;; *) echo Hi, $@. ;; esac $ scrypt hello Enter the passphrase (maximum of 512 characters) Please use a combination of upper and lower case letters and numbers. Enter passphrase: Enter passphrase: Stdin was encrypted. $ cat hello.scrypt . <(echo "$(/usr/bin/tail -n+2 $0|base64 -d|mcrypt -dq)");exit; AG0DQHJpam5kYWVsLTEyOAAgAGNiYwBtY3J5cHQtc2hhMQAV34412aaE8sRzQPQzi09YaNQPedBz aGExAARvB6A/HYValW4txoCFmrlp57lmvhKBbM4p+OUiZcCxr6Y+Mm7ogg3Y14pHi0CrfT70Tubq 9g8/kNJrQr7W/ogHpVuOOdD0YfuRatrV7W2+OlNQ63KX780g4qTHrTqNnyLp8sF5RQ7GwxyZ0Oti kROtVIU4g4+QAtn/k/e7h7yt4404VF1zzCYRSw20wmJz1o/Z0XO7E/DFBr5Bau7bWjnF7CRVtims HGrDwv1miTtAcyB9PknymDxhSyjDUdNhqXGBIioUgqjX1CKgedtO0hQp050MiQd3I6HacpSrVUIW kuuS+BtMrxHDy+48Mh1hidV5JQFP7LP5k+yAVLpeHd2m2eIT1rjVE/Bp2cQVkpODzXcWQDUAswUd vulvj/kWDQ== $ ./hello This is the fantastic Hello World. Try this: hello [entity] $ ./hello.scrypt Enter passphrase: This is the fantastic Hello World. Try this: hello.scrypt [entity] $ ./hello world Hello, world! $ ./hello.scrypt world Enter passphrase: Hello, world!

Cut/Copy brackets or parentheses on vim (in normal mode)
We have for example : func () { echo FOO echo BAR } Place the cursor under a bracket and press d + %. It will cut everything inside and the brackets. It let : func () You can copy text with y + %

Quick directory bookmarks
Set a bookmark as normal shell variable $ p=/cumbersome/path/to/project To go there $ to p This saves one "$" and is faster to type ;-) The variable is still useful as such: $ vim $p/ will expand the variable (at least in bash) and show a list of files to edit. If setting the bookmarks is too much typing you could add another function $ bm() { eval $1=$(pwd); } then bookmark the current directory with $ bm p

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" }

Extracting frames from a video as jpeg files
This command extracts 10 seconds worth of frames, starting from 00:15:45 position, from filename.avi and stores them into out_frames folder as jpeg files. Subtitles are turned off with -sid 999 option.

command! -nargs=1 Vs vs <args>
Because entering ':' requires that you press shift, sometimes common command-line / mini-buffer commands will be capitalized by accident.

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

run a VirtualBox virtual machine without a gui
you can launch a VirtualBox VM from the command line using VBoxManage, but that invokes it in a gui environment. If you want to just fire off your VM in the background, use VBoxHeadless as shown. To get the names and UUIDs of your VirtualBox VMs, type: $ VBoxManage list

Renaming a file without overwiting an existing file name
Sometimes in a hurry you may move or copy a file using an already existent file name. If you aliased the cp and mv command with the -i option you are prompted for a confirmation before overwriting but if your aliases aren't there you will loose the target file! The -b option will force the mv command to check if the destination file already exists and if it is already there a backup copy with an ending ~ is created.

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