Finding out the active Unix shell

[Tom Gur]

Hi,

It's seems that csh and tcsh acts a bit different when handling
special characters in quotes.
i.e: if i'll supply my program with the following arguments: -winpath
"c:\\temp\\ "
tcsh will take it as -winpath "c:\temp\"
and csh will take it literally (with the double-slashes).

Is there a way for me to know what shell is currently running my
program, so I could fit a different code for each shell ?

[mark_bluemel]

On 7 Jun, 08:22, Tom Gur <gur....@gmail. comwrote:

Hi,

It's seems that csh and tcsh acts a bit different when handling
special characters in quotes.
i.e: if i'll supply my program with the following arguments: -winpath
"c:\\temp\\ "
tcsh will take it as -winpath "c:\temp\"
and csh will take it literally (with the double-slashes).

Is there a way for me to know what shell is currently running my
program, so I could fit a different code for each shell ?

Not in the C language per se.

I suggest you ask the question in comp.unix.progr ammer.

[Joachim Schmitz]

"Tom Gur" <gu*****@gmail. comschrieb im Newsbeitrag
news:11******** **************@ o5g2000hsb.goog legroups.com...

Hi,

It's seems that csh and tcsh acts a bit different when handling
special characters in quotes.
i.e: if i'll supply my program with the following arguments: -winpath
"c:\\temp\\ "
tcsh will take it as -winpath "c:\temp\"
and csh will take it literally (with the double-slashes).

Is there a way for me to know what shell is currently running my
program, so I could fit a different code for each shell ?

What has this got to do with C and why do you post this question in
comp.lang.c?

the environment variable $SHELL might help. But you may also check in
comp.unix.progr ammer

Bye, Jojo

[Keith Thompson]

Tom Gur <gu*****@gmail. comwrites:

It's seems that csh and tcsh acts a bit different when handling
special characters in quotes.

[snip]

Ask in comp.unix.shell .

--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <* <http://users.sdsc.edu/~kst>
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"

[Tom Gur]

Maybe I wasn't clear.
I'm writing a C program (a server) that runs a Java program (an agent)
with some arguments.
The agent's shell is unknown, so I need to check, within my C code
what kind of shell runs on the account that runs the agent.
I was wondering whether you know any kind of function that can get
environment variables - so I'll be able to check the value of $SHELL
in the agent's machine.

Thanks

[mark_bluemel]

On 7 Jun, 10:07, Tom Gur <gur....@gmail. comwrote:

Maybe I wasn't clear.

Or maybe you weren't listening.

I'm writing a C program (a server) that runs a Java program (an agent)
with some arguments.
The agent's shell is unknown, so I need to check, within my C code
what kind of shell runs on the account that runs the agent.

I was wondering whether you know any kind of function that can get
environment variables - so I'll be able to check the value of $SHELL
in the agent's machine.

In the C language as such there won't be any such thing.

In the Unix APIs there may be an appropriate function but that's not
in the remit of this group.

You'll get better answers in a group relating to Unix - most likely
comp.unix.progr ammer.

<OffTopic>
Unix has getenv() but the $SHELL variable does not seem to be altered
if a new shell is launched.

And as to why anyone would use C shells, I despair...
</OffTopic>

[Richard Tobin]

In article <11************ *********@q75g2 000hsh.googlegr oups.com>,
Tom Gur <gu*****@gmail. comwrote:

>Maybe I wasn't clear.
I'm writing a C program (a server) that runs a Java program (an agent)
with some arguments.
The agent's shell is unknown, so I need to check, within my C code
what kind of shell runs on the account that runs the agent.

You're still not very clear. How are you running the program?

>I was wondering whether you know any kind of function that can get
environment variables - so I'll be able to check the value of $SHELL
in the agent's machine.

You can use the C function getenv(), but since you talk about "the
agent's machine" and "the account that runs the agent" it sounds
as if testing an environment variable in the server isn't going to
do much good. Perhaps you could have the server run a small program
on the other machine that does 'getenv("SHELL" )'.

-- Richard
--
"Considerat ion shall be given to the need for as many as 32 characters
in some alphabets" - X3.4, 1963.

[Richard Bos]

ma**********@po box.com wrote:

On 7 Jun, 10:07, Tom Gur <gur....@gmail. comwrote:

I was wondering whether you know any kind of function that can get
environment variables - so I'll be able to check the value of $SHELL
in the agent's machine.

In the C language as such there won't be any such thing.

Yesno.

In the Unix APIs there may be an appropriate function but that's not
in the remit of this group.

You'll get better answers in a group relating to Unix - most likely
comp.unix.progr ammer.

<OffTopic>

Not yet.

Unix has getenv()

Actually, that's an ISO C function, but...

but the $SHELL variable does not seem to be altered if a new shell is launched.

....C makes no guarantees about which variables are available, let alone
what they mean.

So the OP could easily use a C function, but _how_ he should use this
function does depend on the OS he uses (and frustratingly, could even
depend on the shell he uses... so to find out which shell he has, he
first has to find out which shell he has. Nice.)

Richard

[Flash Gordon]

ma**********@po box.com wrote, On 07/06/07 10:20:

On 7 Jun, 10:07, Tom Gur <gur....@gmail. comwrote:

>Maybe I wasn't clear.

Or maybe you weren't listening.

>I'm writing a C program (a server) that runs a Java program (an agent)
with some arguments.
The agent's shell is unknown, so I need to check, within my C code
what kind of shell runs on the account that runs the agent.

>I was wondering whether you know any kind of function that can get
environment variables - so I'll be able to check the value of $SHELL
in the agent's machine.

In the C language as such there won't be any such thing.

In the Unix APIs there may be an appropriate function but that's not
in the remit of this group.

You'll get better answers in a group relating to Unix - most likely
comp.unix.progr ammer.

<OffTopic>
Unix has getenv() but the $SHELL variable does not seem to be altered
if a new shell is launched.

getenv is actually part of the C standard, so the ability to use it to
access environment variable is topical here. However, what environment
variables are available and what they do is not topical, so you are
correct that comp.unix.progr ammer is a better place for the OP to ask.

And as to why anyone would use C shells, I despair...
</OffTopic>

Possibly because they like them :-)
--
Flash Gordon

[Mark McIntyre]

On Thu, 07 Jun 2007 09:07:54 -0000, in comp.lang.c , Tom Gur
<gu*****@gmail. comwrote:

>Maybe I wasn't clear.
I'm writing a C program (a server) that runs a Java program (an agent)
with some arguments.
The agent's shell is unknown, so I need to check, within my C code
what kind of shell runs on the account that runs the agent.

The answer is unfortunatly still the same. You need to ask the
specialists in your os and /or compiler, since C itself has no
facilities for doing this. Most probably there's a function called
getenv() or something similar provided by your platform.
--
Mark McIntyre

"Debugging is twice as hard as writing the code in the first place.
Therefore, if you write the code as cleverly as possible, you are,
by definition, not smart enough to debug it."
--Brian Kernighan