# scd - smart change of directory
  
  Define `scd` shell function for changing to any directory with
  a few keystrokes.
  
  `scd` keeps history of the visited directories, which serves as an index of
  the known paths.  The directory index is updated after every `cd` command in
  the shell and can be also filled manually by running `scd -a`.  To switch to
  some directory, `scd` needs few fragments of the desired path to match with
  the index.  A selection menu is displayed in case of several matches, with a
  preference given to recently visited paths.  `scd` can create permanent
  directory aliases, which appear as named directories in zsh session.
  
  ## INSTALLATION NOTES
  
  Besides oh-my-zsh, `scd` can be used with *bash*, *dash* or *tcsh*
  shells and is also available as [Vim](http://www.vim.org/) plugin and
  [IPython](http://ipython.org/) extension.  For installation details, see
  https://github.com/pavoljuhas/smart-change-directory.
  
  ## SYNOPSIS
  
  ```sh
  scd [options] [pattern1 pattern2 ...]
  ```
  
  ## OPTIONS
  
  <dl><dt>
  -a, --add</dt><dd>
    add specified directories to the directory index.</dd><dt>
  
  --unindex</dt><dd>
    remove current or specified directories from the index.</dd><dt>
  
  -r, --recursive</dt><dd>
    apply options <em>--add</em> or <em>--unindex</em> recursively.</dd><dt>
  
  --alias=ALIAS</dt><dd>
    create alias for the current or specified directory and save it to
    <em>~/.scdalias.zsh</em>.</dd><dt>
  
  --unalias</dt><dd>
    remove ALIAS definition for the current or specified directory from
    <em>~/.scdalias.zsh</em>.</dd><dt>
  
  -A, --all</dt><dd>
    include all matching directories.  Disregard matching by directory
    alias and filtering of less likely paths.</dd><dt>
  
  --list</dt><dd>
    show matching directories and exit.</dd><dt>
  
  -v, --verbose</dt><dd>
    display directory rank in the selection menu.</dd><dt>
  
  -h, --help</dt><dd>
    display this options summary and exit.</dd>
  </dl>
  
  ## Examples
  
  ```sh
  # Index recursively some paths for the very first run
  scd -ar ~/Documents/
  
  # Change to a directory path matching "doc"
  scd doc
  
  # Change to a path matching all of "a", "b" and "c"
  scd a b c
  
  # Change to a directory path that ends with "ts"
  scd "ts$"
  
  # Show selection menu and ranking of 20 most likely directories
  scd -v
  
  # Alias current directory as "xray"
  scd --alias=xray
  
  # Jump to a previously defined aliased directory
  scd xray
  ```
  
  # FILES
  
  <dl><dt>
  ~/.scdhistory</dt><dd>
      time-stamped index of visited directories.</dd><dt>
  
  ~/.scdalias.zsh</dt><dd>
      scd-generated definitions of directory aliases.</dd>
  </dl>
  
  # ENVIRONMENT
  
  <dl><dt>
  SCD_HISTFILE</dt><dd>
      path to the scd index file (by default ~/.scdhistory).</dd><dt>
  
  SCD_HISTSIZE</dt><dd>
      maximum number of entries in the index (5000).  Index is trimmed when it
      exceeds <em>SCD_HISTSIZE</em> by more than 20%.</dd><dt>
  
  SCD_MENUSIZE</dt><dd>
      maximum number of items for directory selection menu (20).</dd><dt>
  
  SCD_MEANLIFE</dt><dd>
      mean lifetime in seconds for exponential decay of directory
      likelihood (86400).</dd><dt>
  
  SCD_THRESHOLD</dt><dd>
      threshold for cumulative directory likelihood.  Directories with
      a lower likelihood compared to the best match are excluded (0.005).
      </dd><dt>
  
  SCD_SCRIPT</dt><dd>
      command script file where scd writes the final <code>cd</code>
      command.  This variable must be defined when scd runs in its own
      process rather than as a shell function.  It is up to the
      scd caller to use the output in <em>SCD_SCRIPT</em>.</dd>
  </dl>