function::system - Linux

Overview

function::system is a command-line tool used to execute system commands from within Bash functions. It provides a convenient way to run external commands as part of a function, enabling more complex and automated workflows.

Syntax

function::system [-h] [-v] [-e] [-i] [-s] [-f] [-p] [-l] [-c COMMAND]

Options/Flags

  • -h, --help: Display help message and exit.
  • -v, --verbose: Enable verbose output, showing the executed command and its results.
  • -e, --exit-on-error: Exit the function immediately if the executed command returns an error.
  • -i, --interactive: Enable interactive mode, prompting the user for input before executing the command.
  • -s, --silent: Suppress all output from the executed command.
  • -f, --filter-output: Filter the output of the executed command using the specified regular expression.
  • -p, --pipe-output: Pipe the output of the executed command to the standard output.
  • -l, --log-output: Log the output of the executed command to the specified file.
  • -c COMMAND, --command COMMAND: Specify the command to be executed.

Examples

Simple usage: Execute a system command and print its output:

function::system "echo Hello World!"

Verbose output: Enable verbose mode to see the executed command:

function::system -v "ls -l"

Exit on error: If the command fails, exit the function immediately:

function::system -e "rm -rf /"

Interactive mode: Prompt the user for input before executing the command:

function::system -i "read -p 'Enter a value: ' value; echo $value"

Filter output: Filter the output of the command using a regular expression:

function::system -f "grep error" "dmesg"

Pipe output: Pipe the output of the command to another command:

function::system -p "ls -l" | less -R

Log output: Log the output of the command to a file:

function::system -l /tmp/command-output.log "ls -l"

Common Issues

  • Permission denied: Ensure that the current user has sufficient permissions to execute the specified command.
  • Syntax error: Check the command syntax carefully for any typos or incorrect usage.
  • Path not found: Verify that the specified command is available in the system’s PATH environment variable.

Integration

function::system can be combined with other commands or tools to create complex workflows. For instance, it can be used within Bash scripts to conditionally execute commands:

if [[ $(function::system "ls -l /path/to/file") ]]; then
  echo "File exists."
fi

Related Commands

  • sh: Run a shell command.
  • bash: Run a Bash script.
  • command: Execute a single command.