Add a line on top of each Python file in current and subdirectories

Question

I am on the Ubuntu platform and have a directory containing many .py files and subdirectories (also containing .py files). I would like to add a line of text at the beginning of each .py file. The easiest way to do this using Perl, Python, or a shell script?

Answer 1

#!/usr/bin/perl use Tie::File; for (@ARGV) { tie my @array, 'Tie::File', $_ or die $!; unshift @array, "A new line"; } 

To process all .py files in a directory, execute this command recursively in your shell:

find . -name '*.py' | xargs perl script.pl

Answer 2

 find . -name \*.py | xargs sed -i '1a Line of text here' 

Edit: from tchrist comment, handle file names with spaces.

Assuming you have a GNU search and xargs (as you pointed the linux tag to the question)

 find . -name \*.py -print0 | xargs -0 sed -i '1a Line of text here' 

Without GNU tools, you would do something like:

 while IFS= read -r filename; do { echo "new line"; cat "$filename"; } > tmpfile && mv tmpfile "$filename" done < <(find . -name \*.py -print) 

Answer 3

 for a in `find . -name '*.py'` ; do cp "$a" "$a.cp" ; echo "Added line" > "$a" ; cat "$a.cp" >> "$a" ; rm "$a.cp" ; done 

Answer 4

 import os for root, dirs, files in os.walk(directory): for file in files: if file.endswith('.py') file_ptr = open(file, 'r') old_content = file_ptr.read() file_ptr = open(file, 'w') file_ptr.write(your_new_line) file_ptr.write(old_content) 

As far as I know, you cannot insert the beginning or end of a file in python. Only rewrite or add.

Answer 5

This will

• recursively go through all directories starting from the current working directory
• Only change files whose filename ends with ".py"
• save file permissions (unlike open(filename,'w') .)

fileinput also gives you the ability to back up source files before modifying them.

---

 import fileinput import os import sys for root, dirs, files in os.walk('.'): for line in fileinput.input( (os.path.join(root,name) for name in files if name.endswith('.py')), inplace=True, # backup='.bak' # uncomment this if you want backups ): if fileinput.isfirstline(): sys.stdout.write('Add line\n{l}'.format(l=line)) else: sys.stdout.write(line) 

Answer 6

What is the easiest way to do this using Perl, Python or a shell script?

I would use Perl, but that is because I know Perl much better than I know Python. Damn, maybe I'll do it in Python to find out a little better.

The easiest way is to use a language that you are familiar with and can work with. And that, too, is probably the best way.

If these are all Python scripts, I understand that you know Python or have access to a group of people who know Python. So you are probably doing a better project in Python.

However, this is also possible with shell scripts, and if you know what the best shell is, be my guest. Here's a little, completely untested shell script right from my head:

 find . -type f -name "*.py" | while read file do sed 'i\ I want to insert this line ' $file > $file.temp mv $file.temp $file done