how to set/get shell env variable in python script

Shell Programming and Scripting
1

greetings,

i have a sh script that calls a python script. the sh script sets an env variable BIN:

export BIN=bin64

i need to get that BIN variable's value and use it within this python script. anyone know how to do this? thanx in advance.

2

Use getenv in your python script

15.1. os ? Miscellaneous operating system interfaces � Python v2.7.2 documentation

4

mpiRoot is passed as a command line option:

MPI_ROOTDIR=mpiRoot
os.getenv(BIN)
mpdCmd="%s/BIN/mpd" % MPI_ROOTDIR
mpdtraceCmd="%s/BIN/mpdtrace" % MPI_ROOTDIR
mpdtraceCmd2="%s/BIN/mpdtrace -l" % MPI_ROOTDIR

although i replaced the os.getenv with below and succeeded but looking for a more efficient way.

MPI_ROOTDIR=mpiRoot
if MPI_ROOTDIR == "/usr/apps/intel/impi/3.2.2.006":
    Bin="bin64"
else:
    Bin="bin"
mpdCmd="%s/%s/mpd" % (MPI_ROOTDIR, Bin)
mpdtraceCmd="%s/%s/mpdtrace" % (MPI_ROOTDIR, Bin)
mpdtraceCmd2="%s/%s/mpdtrace -l" % (MPI_ROOTDIR, Bin)
5

It works for me! Check below:

# export BIN="123456789"
# python
Python 2.3.4 (#1, Jul 16 2009, 07:03:37)
[GCC 3.4.6 20060404 (Red Hat 3.4.6-11)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import os
>>> print os.getenv('BIN')
123456789

If you are using: "os.getenv(BIN)" and BIN, in this context in not a variable, it will not work! It must be between quotes (single or double).

I hope it helps.

6

that works for me as well HOWEVER:

# export BIN=bin64
# python
Python 2.4.3 (#1, Jun 11 2009, 14:09:37)
[GCC 4.1.2 20080704 (Red Hat 4.1.2-44)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import os
>>> print os.getenv('BIN')
bin64
>>>

how do i get that "BIN" to be recognized on the code i posted in my second post? therein lies my issue. thanx.

7

In the same way as you are doing as a command line argument:

def getEnvVarValue(envVar):
    tmpVal = os.getenv(envVar)
    if not tmpVal:
        print("Environment variable: [%s] not set." % (envVar))
        sys.exit(1)
        
    retValue = tmpVal.strip("'") 
    return retValue


Bin=getEnvVarValue('BIN')
mpdCmd="%s/%s/mpd" % (MPI_ROOTDIR, Bin)
mpdtraceCmd="%s/%s/mpdtrace" % (MPI_ROOTDIR, Bin)
mpdtraceCmd2="%s/%s/mpdtrace -l" % (MPI_ROOTDIR, Bin)

I hope it helps!