Introduction to xargs with Basic and Advanced Usage Examples

xargs is a Unix command that reads arguments from standard input, assembles them into a command line, and executes the resulting command, making it useful for turning many single‑line commands into efficient batch operations.

Basic xargs example: The command ls *.log | xargs cat lists all .log files in the current directory and feeds their names to xargs cat , which concatenates and outputs their contents.

Advanced xargs example: To rename every .txt file to .log in a directory, you can use: ls *.txt | awk -F '.' '{print $1}' | xargs -I{} mv {}.txt {}.log

The -I option tells xargs to replace each occurrence of {} in the following command with the input string (e.g., aaa ), resulting in commands like mv aaa.txt aaa.log that are executed sequentially.

The article also outlines the processing steps: ls outputs file names to standard output. awk splits each name at the dot and outputs the base name. xargs receives the base name, substitutes it for {} , and constructs the mv command. The mv command renames the file from .txt to .log .

Note: the provided command sequence has a known bug, left as an exercise for readers to improve.