passing asterisk to a script as variable

GKnight · #1 (**permalink**) 04-01-2008

I'm writing a script that will ssh to a number of hosts and run commands. I'm a bit stumped at the moment as some of the commands that I need to run contain wildcards (i.e. *), and so far I have not figured out how to escape the * character so the script doesn't expand it. More specifically, here's an excerpt of the script.

Quote:

#!/bin/sh

COMMAND="$@"

for HOST in `cat $INFILE | grep -v ^#`
do
echo "============== $HOST ==============="
echo " "
ssh $HOST $COMMAND
echo " "
echo " "
done

Let's say I'm trying to pass a command some_command * options to the script. No matter how I tried escaping the *, $@ variable always converts it to the list of files. Any ideas on how to fix this?

vgersh99 · #2 (**permalink**) 04-01-2008

Code:

some_command '*' options

GKnight · #3 (**permalink**) 04-01-2008

No go... already tried that. * is still expanded into the list of files in current directory. Backslash doesn't work, either.

cfajohnson · #4 (**permalink**) 04-01-2008

Quote:

Originally Posted by GKnight

I'm writing a script that will ssh to a number of hosts and run commands. I'm a bit stumped at the moment as some of the commands that I need to run contain wildcards (i.e. *), and so far I have not figured out how to escape the * character so the script doesn't expand it. More specifically, here's an excerpt of the script.

Let's say I'm trying to pass a command some_command * options to the script. No matter how I tried escaping the *, $@ variable always converts it to the list of files. Any ideas on how to fix this?

Quote the variables. It is not $@ that expands the asterisk, but the shell that called the script.

You will also have to escape the asterisk:
[CODE]
COMMAND="whatever \* whatever"
ssh "$HOST" "$COMMAND"
{/CODE]

GKnight · #5 (**permalink**) 04-01-2008

Nope, still doesn't work... I tried that one as well. It doesn't expand the file list anymore, but then I have the backslash as part of my variable (see below for an example).

I'm not sure it's the shell that's expanding the variable:

Code:

$ echo "some_command \* options"
some_command \* options
$ echo "some_command * options"
some_command * options

cfajohnson · #6 (**permalink**) 04-01-2008

Quote:

Originally Posted by GKnight

Nope, still doesn't work... I tried that one as well. It doesn't expand the file list anymore, but then I have the backslash as part of my variable (see below for an example).

I'm not sure it's the shell that's expanding the variable:

The shell is the only thing that does expand wildcards, unless you have written something else to do it.

Quote:

Code:

$ echo "some_command \* options"
some_command \* options
$ echo "some_command * options"
some_command * options

The wildcard will not be expanded if it is quoted.

Quote:

meanwhile, by adding "echo $COMMAND" to my script, I get:

Code:

./test-script "some_command * options"
some_command ...list of files... options

./test-script "some_command \* options"
some_command \* options

I tried running the script from bash and ksh with the same results.

Always quote your variables (unless you have a good reason not to):

Code:
ssh "$HOST" "$COMMAND"

rubin · #7 (**permalink**) 04-01-2008

As previously stated in an ssh script, the commands ( and eventually all the special characters in them, for example: *, $, ...) will be evaluated first by the current shell, before ssh-in.

So you need to properly escape all of them. For more check these threads:

How to execute multiple commands via ssh

IF condition failing in a SSH script

-

More UNIX and Linux Forum Topics You Might Find Helpful
Thread	Thread Starter	Forum	Replies	Last Post
Newbie Question: passing a variable into java from script?	Cailet	Shell Programming and Scripting	1	10-18-2007 10:31 PM
passing variable to my script	aladdin	UNIX for Dummies Questions & Answers	5	06-18-2007 10:34 AM
Passing a variable into an awk script	Khoomfire	UNIX for Advanced & Expert Users	5	09-05-2006 09:44 AM
passing ip address as a variable to script for ftp	Gerry405	UNIX for Dummies Questions & Answers	2	09-01-2005 06:26 AM
passing awk variable to the shell script	bcheaib	Shell Programming and Scripting	3	07-21-2004 11:00 AM

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Display Modes	Rate This Thread
Switch to Linear Mode Hybrid Mode Switch to Threaded Mode	Rate This Thread: