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Article ID: KB23008 KB Last Updated: 16 May 2012Version: 1.0
JUNOS created a child processes to execute certain commands, but during execution of the commands, JUNOS was unable to detect input on a stream connected to a child process.
The problem observed for this syslog message is described in the following sections:
  • Symptom
  • Possible Causes
  • Confirmed Causes

Messages similar to the following will appear in the log messages file:
Unable to select input stream for command '<command>':<error-message>


LIBJNX_EXEC_SELECT: Unable to select input stream for command 'fbuf pipe': Bad file descriptor


An internal software failure occurred. The message means that one of the file descriptors which mgd is tracking is either mishandled, or is somehow lost.


Examine the following outputs:

show log messages
show log cli-commands (i.e. system log message file where 'interactive-commands' knob is configured)

Observe any correlations there are any JUNOScript, Netconf, SNMP, or other Network Management system scripts/servers which are performing commands/changes in the CLI commands when these messages are observed in the messages log.

Also, check the script and any related XML schema to ensure that the proper syntax is being used and not terminating the script unexpectedly and/or at an incorrect point/timing.

Perform these steps:
  1. Follow the instructions under 'Confirmed Causes'.
  2. If the message occurs only one time in the log messages, it can be ignored.
  3. If the failure messages continue to occur, open a case with your technical support representative to investigate the issue further.

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