how to use scp inside ssh in a shell script - scp

Question

I have a server ServerA ( user1 as userid) .I want to connect to same server ServerA with userid as user2 and then do scp to get files from other server and keep in ServerA server(userid as user2).
Could anyone please help me out asap.

Answer 1

Wouldn't it be easier to do the scp as user1, then chown the files to user2? If you need to store them in a place accessible only to user2 you could su to user2 and move them.

Answer 2

Say you're on hostC (client) and you want to copy files from userX#hostA to userY#hostB.
You can issue an scp command on hostC:
scp userX#hostA:file-to-copy userY#hostB:destination-folder/
However, you need to authenticate. If you have an ssh key set up for userX#hostA key authentication will work fine.
However scp will invoke ssh with options to either disable agent forwarding or clear forwarding keys, so that even if you have a key for userY#hostB it won't be available to hostB and you'll be prompted for a password.
One solution to this is to pass a -S <ssh-command> to the invocation of scp on hostC with a wrapper script to strip out the options that prevent agent forwarding, perhaps having to explicitly enable it.
e.g.
ssh-wrapper.py
#!/usr/bin/python
import sys, os
def is_exe(fpath):
return os.path.exists(fpath) and os.access(fpath, os.X_OK)
def which(program):
fpath, fname = os.path.split(program)
if fpath:
if is_exe(program):
return program
else:
for path in os.environ["PATH"].split(os.pathsep):
exe_file = os.path.join(path, program)
if is_exe(exe_file):
return exe_file
return None
if __name__ == '__main__':
ssh = which('ssh')
assert ssh is not None
args = [ssh] + sys.argv[1:]
for x in ('-a','-oClearAllForwardings yes'):
if x in args:
args.remove(x)
if '-oForwardAgent yes' not in args:
args.insert(1,'-oForwardAgent yes')
os.execl(ssh,*args)
Invoking scp:
scp -S ssh-wrapper.py userX#hostA:file-to-copy userY#hostB:destination-folder/