feholdexcept - Linux


feholdexcept is a utility that allows users to put the current terminal into hold and except input from specified files or pipes. It is useful for running commands and waiting for input from a specific source, monitoring multiple input sources, or automating tasks.


feholdexcept [-h] [--version] [-i INPUT_FILE] [COMMAND]


  • -h, –help: Display help message.
  • –version: Show version information.
  • -i, –input: File or pipe from which to read input. Multiple files can be specified.


Run a command and wait for input from a file:

feholdexcept -i input.txt command

Monitor multiple input sources:

feholdexcept -i input1.txt -i input2.txt command

Automate a task using a script:



# Run the command in a loop, waiting for input from the file
while read -r line; do
  # Process the input line
  echo "$line"

  # Check if the process has timed out
  if [ $timeout -gt 0 ]; then
    echo "Timeout reached. Exiting."
    exit 1
done < "$in_file"

Common Issues

  • Command does not start: Ensure that the command you want to run is valid and that feholdexcept is invoked with the correct input files.
  • Input loop terminates prematurely: If the timeout is not set, the input loop will terminate once all input files have been processed.
  • Unwanted input: Verify that the input files or pipes do not contain unwanted data that could interfere with the command execution.


feholdexcept can be combined with other commands to create complex workflows:

  • tail -f | feholdexcept: Monitor the output of a command live.
  • feholdexcept -i pipe_command: Read input from a pipe created by another command.
  • watch feholdexcept -i input.txt: Monitor the input file for changes and run the command whenever new data is available.

Related Commands

  • watch: Monitor a command and display its output periodically.
  • tail: Print the last part of a file or stdin.
  • more: Read a file or stdin one page at a time.