Question

I am having problems using a program called ‘ccrypt’ which is used to encrypt files. The way in which I am using it is as follows:

ccrypt -e -E $cryptograph `find . -type f | sed -n -e '$i{p;q}'`

where -e means that the program is running in encrypt mode. My problem is as follows:

The manual for the command says that -E is used to read the passphrase for the encryption from an environment variable using this syntax:

-E var

and as such I have set it to be the passphrase I want as below:

cryptograph="Example_passphrase"

However, when I run the code as shown above, an error message appears as follows:

ccrypt: environment variable Example_passphrase does not exist.

Does anybody have any idea what I am doing wrong?

EDIT:
Thanks for the answers, exporting the variable and removing the “$” worked but now I face a new problem:

"sed -n -e '$i{p;q}'"

The shell says:

ccrypt: {p;q}: No such file or directory

However, if I exchange $i for a number then the program works to an extent. What is the correct syntax for using the variable ‘i’ here?

Answer 1

Don’t forget to export the environment variable (until it is exported, it is just a variable, not an environment variable).

export cryptograph="Example_passphrase"
ccrypt -e -E cryptograph `find . -type f | sed -n -e '$i{p;q}'`

Specifying just the name is crucial (no $). Otherwise, the value of the variable — the passphrase itself — is in the command line arguments and visible to ps etc. We can debate whether the environment is secure (think of the /proc file system), but it is several steps better than including the passphrase itself on the command line.

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From the comments, it appears that you might be best off doing something like:

find . -type f -exec ccrypt -e -E cryptograph {} ';'

One major advantage of this is that it sidesteps all the problems with blanks and other odd-ball characters in file names. If the ccrypt command accepts multiple files, you can probably replace the quoted ';' with + (which doesn’t need quotes) and a single command will encrypt all the files.