How to pass inputs to a shell script in automator

automatorservices

I want to pass the filename of the file I rightclicked to a shell script through automator:

# encrypt file.txt to file.enc using 256-bit AES in CBC mode
openssl enc -aes-256-cbc -salt -in file.txt -out file.txt.enc

When I create a 'service' I can pass on the input 'as arguments', but how to I implement it in the code?
It would be great if the file could be called 'file.enc' instead of 'file.txt.enc' if that is possible.

Best Answer

pass=$(osascript -e 'tell app (path to frontmost application as text)
text returned of (display dialog "Enter password:" default answer "")
end')
for f in "$@"; do
    printf %s "$pass" | openssl enc -aes-256-cbc -salt -in "$f" -out "${f%.*}.enc" -pass stdin
done

Related Solutions

Running a gpg shell script to decrypt a file via Automator

The Automator “Run Shell Script” action runs the script in a non-interactive shell (for an explanation of the difference between interactive and non-interactive shells, see the pertinent section of the Advanced Bash Scripting Guide) – there is, simply spoken, no terminal to get user input from. I suppose the gpg utility recognizes this and skips the password prompt (else your script would hang).

You should be able to pipe your passphrase to GPG inside such an action using the --passphrase-fd 0 option (see gpg’s man page) , however, i.e.

echo "passphrase" |  gpg  --passphrase-fd 0 --output $outfile --decrypt /path/to/file.gpg

You can securely store your passphrase in the OS X Keychain and retrieve it from there. Although possible via a shell script (the TextMate blog has details on how to achieve that – be sure to read the comments), there are so many gotchas to that I’d recommend using a bit of AppleScript and Daniel Jalkut’s excellent Usable Keychain Scripting app. Once installed, the following bit of AppleScript will retrieve your password (assuming the account name is “GPG”):

tell application "Usable Keychain Scripting" to get password of first generic item of current keychain whose account is "GPG"

Either wrap it in an osascript shell command, i.e.

passphrase=$(osascript -e '<command above>')

or, as you are using Automator, add an AppleScript action, retrieve the passphrase inside it and pass it to the shell script.

Create Automator Service With a Python Script

This isn't too difficult to do, you just need to know the right magic. I'll walk you through it.

Open Automator, and when prompted to choose a type for your document, select Service. If you're not prompted, just hit ⌘N to make a new automator file.
At the top of the rightmost panel, make sure that Output replaces selected text is checked, and the first drop-down is set to text:
- You can change the any application part to a specific application if you only want it to work in that program.
In the Actions Library in the left panel, find Run Shell Script and double click it to add it to the workflow.
Change the Shell drop down to /usr/bin/python, and make sure that Pass input is set to stdin.
Delete the existing text in the script box, and replace it with the code below.
Save it with a descriptive name. Automator will save it in the ~/Library/Services/ folder.
Optional: Go to Keyboard Preferences, and find your service in the Services section of the Keyboard Shortcuts tab. You can assign a system-wide shortcut for it there.

Script Code

import sys

for f in sys.stdin:
    print f.replace('-', ' ').replace('%', ' ').replace('&', ' and ').replace('#', ' ').title(),

Best Answer

Related Solutions

Running a gpg shell script to decrypt a file via Automator

Create Automator Service With a Python Script

Script Code

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