feholdexcept - Linux

Overview

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.

Syntax

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

Options/Flags

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

Examples

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:

#!/bin/bash

in_file=input.txt
timeout=60

# 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 [ $timeout -gt 0 ]; then
    ((timeout--))
  else
    echo "Timeout reached. Exiting."
    exit 1
  fi
done < "$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.

Integration

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.