xargs: How To Control and Use Command Line Arguments

by

The xargs command is a powerful utility that enables a user to take the output of one command and pass it as arguments to another command. Here is an overview of how to control and use command-line arguments with xargs.

The basic syntax for the xargs command is:

command | xargs [options] command

Here, the output of the first command (before the pipe symbol |) is passed as arguments to the second command, which is executed with those arguments.

Some of the useful options available for xargs are:

  • -n: Specifies the number of arguments to be passed to the command.
  • -I: Specifies a placeholder for the argument in the command.
  • -d: Specifies the delimiter for the arguments.
  • -p: Asks for confirmation before executing the command.
  • -r: Prevents the command from being executed if there are no arguments.

Here are a few examples to illustrate how to use some of these options:

  1. Use xargs to delete files that match a pattern:
    find . -name "*.log" | xargs rm

    Here, the find command searches for all files that match the pattern *.log and passes them to xargs. The xargs command then calls the rm command to delete the files.

  2. Use xargs to rename files:
    ls | grep "pattern" | xargs -I{} mv {} {}.new

    Here, the ls command lists all the files in the current directory, the grep command filters the files based on a pattern, and the output is passed to xargs. The -I option specifies a placeholder {} for the argument. The mv command then renames each file with the extension .new.

  3. Use xargs to search for a file:
    echo $PATH | tr ":" "\n" | xargs -I{} find {} -name "filename"

    Here, the echo command prints the PATH environment variable, which contains a list of directories. The tr command replaces the : delimiter with a newline. The output is then passed to xargs, which runs the find command on each directory to search for the file filename.

These are just a few examples of how xargs can be used to control and use command-line arguments. The possibilities are endless, and it is a very useful tool for shell scripting. (Diazepam)

Leave a Comment