Checking for interactive shell sessions [Was: Re: Can't enter passphrase in su session.]

Peter Pentchev roam at
Thu May 21 23:04:23 CEST 2009

On Thu, May 21, 2009 at 01:19:44PM -0400, Steven W. Orr wrote:
> The proper way to deal with this is to:
> * Source in your .bashrc from your .bash_profile
> * Set all of your environment variables in your .bash_profile
> * Check in your .bashrc to see if PS1 is set. If not then you are not in 
> an interactive session and you need to set critical environment variables. 

Just BTW, a *much* more reliable way to check for an interactive
session, which will not fail in many common cases (PS1 set in system-wide
config files, PS1 also set in .bashrc, PS1 set in the environment of
the calling shell, etc.), is the following:

# First, set up all variables for both interactive and non-interactive
# sessions.
# Then, do this:
case "$-" in
                echo 'Setting up interactive shell params..'
                stty erase ^H
		# Non-interactive session, better don't output anything

Of course, substitute your own commands for the "stty" and the assignment :)

Bear in mind that this only applies to Bourne-style shells;
for tcsh, you might need to resort to testing for ($?prompt), indeed.


Peter Pentchev	roam at    roam at    roam at
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What would this sentence be like if pi were 3?
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