Port xargs utility to meniOS

[pbalduino]

Description

Port the xargs utility to meniOS to enable building and executing commands from standard input, making it possible to chain commands effectively in pipelines.

Requirements

Implement a basic xargs utility with essential functionality:

• xargs COMMAND - Read items from stdin and execute COMMAND with them as arguments
• Default behavior: pass all items as arguments to a single command invocation
• Handle multiple arguments per command invocation
• Basic flags (optional):
  • -n MAX - Use at most MAX arguments per command line
  • -I REPLACE - Replace occurrences of REPLACE in COMMAND with names read from stdin
  • -t - Print the command line before executing it
  • -p - Prompt before executing each command

Implementation Details

The utility should:

• Read input from stdin (whitespace or newline delimited)
• Build command lines from the input
• Use fork() and execve() to execute commands
• Handle proper exit status aggregation
• Work with the existing process management syscalls
• Handle edge cases (empty input, command failures, argument list too long)

Usage Examples

$ echo "file1.txt file2.txt file3.txt" | xargs cat
(concatenates all three files)

$ find /tmp -name "*.tmp" | xargs rm
(removes all .tmp files found)

$ echo "world" | xargs -I {} echo "Hello, {}"
Hello, world

$ ls *.c | xargs -n 1 gcc -c
(compiles each .c file separately)

Dependencies

• #193 - Minimal userland libc ✅ (COMPLETE)
• #93 - Fork/exec process creation ✅ (COMPLETE)
• #102 - Pipes implementation ✅ (COMPLETE - for pipeline support)

Acceptance Criteria

• [ ] xargs COMMAND executes command with stdin items as arguments
• [ ] Basic argument batching works (handle whitespace/newlines)
• [ ] Works in pipelines with other utilities
• [ ] Proper exit status handling
• [ ] -n flag for limiting arguments per invocation (optional)
• [ ] -I flag for replacement strings (optional)
• [ ] Test coverage for xargs functionality
• [ ] Documentation/man page entry

Estimated Effort

2-3 days

Priority

Medium - Very useful for composing complex command pipelines

Milestone

Consider for future utility expansion after Mosh milestone completion