clone <remote> \\
          [<repo>]       Clone from an existing repository
-   help                 Display this help text
    delete               Delete an existing repository
    enter                Enter repository; spawn new instance of \$SHELL
+   help                 Display this help text
    init <repo>          Initialize a new repository
    list                 List all repositories
    list-tracked         List all files tracked by vcsh
    run <repo> \\
        <command>        Use this repository
    setup                Set up repository with recommended settings
+   which <substring>    Find substring in name of any tracked file
    write-gitignore \\
    <repo>               Write .gitignore.d/<repo> via git ls-files
 
        for file in $files; do
                rm -f $file || info "could not delete '$file', continuing with deletion"
        done
-       rmdir "$GIT_DIR" || error "could not delete '$GIT_DIR'"
+       rm -r "$GIT_DIR" || error "could not delete '$GIT_DIR'"
 }
 
 enter() {
        export VCSH_DIRECTORY="$VCSH_REPO_NAME"
 }
 
+which() {
+       for VCSH_REPO_NAME in $(list); do
+               for VCSH_FILE in $(get_files); do
+                       echo $VCSH_FILE | grep -q "$VCSH_COMMAND_PARAMETER" && echo "$VCSH_REPO_NAME: $VCSH_FILE"
+               done
+       done | sort -u
+}
+
 write_gitignore() {
        use
        cd "$VCSH_BASE" || fatal "could not enter '$VCSH_BASE'" 11
        [ -n "$3" ] && VCSH_REPO_NAME="$3" || VCSH_REPO_NAME=$(basename "$GIT_REMOTE" .git)
        export VCSH_REPO_NAME
        export GIT_DIR="$VCSH_REPO_D/$VCSH_REPO_NAME.git"
+elif [ "$1" = 'which' ]; then
+       [ -z "$2" ] && fatal "$1: please specify a filename" 1
+       [ -n "$3" ] && fatal "$1: too many parameters" 1
+       export VCSH_COMMAND="$1"
+       export VCSH_COMMAND_PARAMETER="$2"
 elif [ "$1" = 'delete' ]           ||
      [ "$1" = 'enter' ]            ||
      [ "$1" = 'init' ]             ||
 
 verbose "$VCSH_COMMAND begin"
 export VCSH_COMMAND=$(echo $VCSH_COMMAND | sed 's/-/_/g')
+hook pre-command
 $VCSH_COMMAND
+hook post-command
 verbose "$VCSH_COMMAND end, exiting"