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Full Discussion: Shell script debugging
Top Forums Shell Programming and Scripting Shell script debugging Post 302813513 by agama on Monday 27th of May 2013 01:12:30 PM
Old 05-27-2013
Yes, the "DISPLAY" command should execute and pipe it's output to grep. It would help if you could post the whole script, or at least the portions that include the assignment to the DISPLAY variable. It might also help to post the output.

Not knowing exactly what command has been assigned to DISPLAY, I can only guess, and my first thought is that the command's normal output is to standard error and not standard out. This situation could exhibit the behaviour you describe as grep might appear to execute first (failing because of an immediate end of file on standard input?) and the standard error from the command still appearing on the tty device.

Again, that is only a guess, and posting more of the script will certainly help people answer your question.
 

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on(1)							      General Commands Manual							     on(1)

NAME
on - execute command on remote host with environment similar to local SYNOPSIS
| host [command [argument] ... ] DESCRIPTION
executes a command on a remote host, using an environment similar to that of the invoking user where: host specifies the name of the host on which to execute the command. command specifies the command to execute on host If command is not specified, starts a shell on host. argument ... is a list of arguments for command. The user's environment variables are copied to the remote host, and the file system containing the user's current working directory is NFS mounted on the remote host (see nfs(7)). The command is executed on the remote host in the user's current working directory. Commands using relative path names that reference file system objects within the user's current working file system have the same behavior as running the command on the client. The behavior of commands using relative path names that cross the file system boundary or commands using absolute path names depends on the organization of the remote host's file system. Implicit and explicit use of environment variables may also cause a command's behavior to be dependent on the organization of the remote host's file system. For example, the environment variable usually contains absolute path names. Standard input, output and error of the remote command are connected to the appropriate file descriptors on the client. The remote execution daemon does not allow to execute a remote command. The signals and are propagated to the remote command. and are ignored by the remote command. All other signals are delivered to the com- mand. In order to execute a remote command, the remote host must be configured to execute (see rexd(1M)). Options recognizes the following options: Interactive mode. This option is required for commands that must communicate with a terminal such as or Terminal mode changes are propagated to the server. The standard input for an interactive command must be a tty device. The and options are mutually exclusive. Debug mode. Print diagnostic messages during startup of the command. These messages are useful for detecting configuration problems if the command to a specific host is failing. No input mode. This option causes the remote command to get end-of-file (EOF) when it reads from standard input, instead of connecting the standard input of the command to the standard input of the remote command. The option is required when running commands in the background. The and options are mutually exclusive. DIAGNOSTICS
The host name host was not found in the hosts database. The host host is down, unreachable on the network, or not running A problem occurred trying to find the user's current working directory (current_dir). A problem occurred trying to determine the mount point of the user's current working directory (current_dir). The standard input (stdin) of the command with the option is not a tty device. Errors that occur on the server server are propagated back to the client. These messages are documented in the DIAGNOSTICS section of rexd(1M). AUTHOR
was developed by Sun Microsystems, Inc. SEE ALSO
exports(4), rexd(1M). on(1)
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