How to check the existence of an environment variable

[Reggie Chang]

Hi there,

Is there a way to check the existence of an
environment variable?

Something like if ( $CheckThis == "" ) then
in C-Shell would not work. Is getenv an option?
That does not seem to be a standard UNIX command.

Your help is very much appreciated.

Reggie

[Sanjay_6 · Accepted solution]

Hi

"env" is a standard unix command to get env variables.

type env at the prompt and it gives you a list of all env variables currently set.

Hope this helps.

Regds

[RAC_1]

on KSH/sh-posix, the command is set -u

When set -u is doen, script will error ou when undefined variables are accessed.

There should be something similar on csh.

Anil

[Mark Greene_1]

See the man page for printenv which should work in csh.

mark

[Reggie Chang]

Sanjay and RAC,

Thank you for the info.

I use "if ( `env | grep -c CheckMe` == 1 ) then"
in #!/bin/csh and it works fine.

Reggie

[Reggie Chang]

The solution has been found.