OneAndOneIs2

Pretty much everything I do is command-line based these days. So I thought I'd post a few of the things I've found useful lately.

• {}s when moving or copying files.
  You know when you want to copy a file in a directory that isn't your current one? e.g. you're in your home/ and you want to do something to Firefox's userChrome settings. This means copying userChrome-example.css to userChrome.css but the path is a PITA to type twice.
  So instead, you can use curly brackets to make one statement do the work of two:

  cp .mozilla/firefox/profile/chrome/{userChrome-example.css,userChrome.css}

  - much better!
• Useful when you want to edit a file in a non-local directory, as an alias in your .bashrc:

  function vai {
  found=`find . -path *$1`
  vi $found
  }

  So, having created your userChrome file, instead of

  vi .mozilla/firefox/xvuz3pf5.default/chrome/userChrome.css

  you can use the above and simply vai userChrome.css
• If you want to edit a file that isn't just in another directory, but on another server, but using your own local text editor with its nice config files, you don't have to copy it over, edit it, copy it back. Instead, do it all at once:

  vim scp://user@host.name/path/to/file

• Lastly, regex find&replace - often handy, often tricky. So here's an example of one, you can extrapolate from there:
  You want to take a list of filenames

  DSC001.JPEG
  DSC002.JPEG
  DSC003.JPEG
  DSC004.JPEG

  and change them into

  photo_001.jpg
  photo_002.jpg
  photo_003.jpg
  photo_004.jpg

  The command would be:

  :%s/^.\{3\}\([0-9]\{3\}\).*/photo_\1.jpg/g

  which, broken down, means:

  :       - ex command
  %       - every line
  s       - find & replace
  /       - beginning of first term
  ^       - Start at the first character of the line
  .       - any character
  \{3\}   - Three repetitions of the previous character
            (so in this case, any three characters at the start of the line)
  \(      - Opening parentheses of a part of the search that we want to be able 
            to use in the replace text
  [0-9]   - match any number, from 0-9
  \{3\}   - Three repetitions of previous character - here, any three numbers
  \)      - closing parentheses
  .*      - any number of any characters
  /       - End of search term, beginning of replace
  photo_  - replacement text
  \1      - First parenthesised text in the search term, i.e. first \(text\)
  .jpg    - replacement text
  /       - End of replacement term

Hopefully, something or other in there might be useful to the geeks amongst you who use the CLI (or a decent text editor ;o). For anyone else, this post was a baffling waste of time.

Such is life!