Newxt

⚠️ DISCLAIMER: This is a hobby/personal project. Not a commercial product. Not for production use.

Edit files in one pass with instructions via stdin

The replace command performs a simple string replacement on a file based on YAML instructions provided via stdin.

Quick installation (MacOS)

brew install pipx
pipx install newxt

Usage

newxt replace <file> < instructions.yaml

Or using a pipe:

echo "search: old\nreplace: new" | newxt replace myfile.txt

Arguments

• file - Path to the file to perform replacement on (required)

Input Format

The command accepts YAML instructions via stdin with two required fields:

• search - The text to search for in the file
• replace - The text to replace it with

Simple Example

search: old_method
replace: new_method

Multiline Example

For multiline strings, use YAML's literal block scalar syntax:

search: |
  def old_method():
    print("old")
replace: |
  def new_method():
    print("new")

Behavior

• Only the first occurrence of the search string is replaced
• The file is not modified on disk - the result is returned to stdout
• The search is performed as an exact string match (not a regex)
• Both search and replace values must be non-empty

Error Conditions

The command will raise an error if:

• The specified file does not exist
• The path points to a directory instead of a file
• No stdin is provided
• The stdin is not valid YAML
• The search field is missing or blank
• The replace field is missing or blank

Examples

Replace a function name

cat > instructions.yaml << EOF
search: calculate_total
replace: compute_sum
EOF

newxt replace mycode.py < instructions.yaml

Replace a multiline block

cat > instructions.yaml << EOF
search: |
  if debug:
    print("Debug mode")
replace: |
  if self.debug:
    self.logger.debug("Debug mode")
EOF

newxt replace app.py < instructions.yaml > app_updated.py

Using with pipes

echo "search: TODO\nreplace: DONE" | newxt replace notes.txt

Notes

• The command returns the modified content to stdout
• To save the result, redirect the output to a new file
• The original file remains unchanged
• Whitespace and indentation in the search string must match exactly