iSelect -- Interactive Selection Tool

iselect [-d STR,STR] [-c] [-f] [-a] [-e] [-p NUM] [-k KEY[:OKEY]] [-m] [-n STR] [-t STR] [-S] [-K] [-P] [-Q STR] [line1 line2 ...]

iselect [-V]

1.2.0 (31-Mar-1999)

iSelect is an interactive line selection tool for ASCII files, operating via a full-screen Curses-based terminal session. It can be used either as an user interface frontend controlled by a Bourne-Shell, Perl or other type of script backend as its wrapper, or in batch as a pipe filter (usually between grep and the final executing command). In other words: iSelect was designed to be used for any type of interactive line-based selection.

Input is read either from the command line (line1 line2 ...) where each argument corresponds to one buffer line or from stdin (when no arguments are given) where the buffer lines are determined according to the newline characters.

You can additionally let substrings displayed in Bold mode for non-selectable lines (because the selectable lines are always displayed bold) by using the construct CW<b>...CW</b> as in HTML.

The selection is either just a single line (default) or multiple lines (option -m). Per default no lines are selectable. If a line contains the string CW<s> (or a string with different delimiters configured via option -d) at any position this string is stripped and the line is selectable. Its result (printed to stdout) is the line contents itself (but without the CW<s> string of course). If option -a is used all lines are selectable and their result is again the line itself, i.e. using option -a is the same as adding CW<s> to every line of the input data. When you want a specific result (i.e. not just the line contents itself), you have to use the special variant CW<s:result text> which results in the output CWresult text when the corresponding line is selected.

When you use a specific result via CW<s:result text> the result text can contain CW%s[query text]s and CW%s[query text]S constructs. For every such construct an interactive query is done and the result replaces the construct. The CW%s[query text]S construct is like CW%s[query text]s except that the empty string as the query result is not accepted on input.

The Curses-based full-screen selection is always done via /dev/tty, because the stdin and stdout filehandles are usually tied to the input and output data streams.

The output is the line itself or the string given with CW<s:result text>. When multiple line selection mode (option -m) is used the output is all selected lines, or their configured result strings. Output always is written to stdout.

These options control how iSelect parses its input.

-d STR, --delimiter=STR

Sets the delimiters for the selection tags. The default is CW<,>, i.e. the selection tags have to read CW<s> and CW<s:result text>.

-c, --strip-comments

Strips all sharp comment lines from the input buffer before parsing.

-f, --force-browse

Browse always, i.e. even when the input buffer contains no or only one line.

-a, --all-select

Force all lines to be selectable.

-e, --exit-no-select

Exit immediately if no lines are selectable. In this case not even the Curses screen is initialized.

-p NUM, --position=NUM

Sets the cursor position to line NUM.

-k KEY[:OKEY], --key=KEY[:OKEY]

Defines an additional input key. Per default OKEY is CWRETURN, i.e. for instance -kf defines another selection key CWf.

-m, --multi-line

Enable multi-line selection where you can select more then one line via SPACE key.

-n STR, --name=STR

Sets the name string, displayed flush left at the bottom of the browser window.

-t STR, --title=STR

Sets the title bar string, displayed centered at the bottom of the browser window.

-S, --strip-result

Strip all leading and trailing whitespaces from the result string.

-K, --key-result

Prefix the result string (given on stdout) with the corresponding selection key which was used. This usually is CWRETURN or CWKEY_RIGHT but can be any of the additional keys defined by option -k. When you use -kf and select a line CWFoo Bar with key CWf the result string is CWf:Foo Bar.

-P, --position-result

Prefix the result string (given on stdout) with the corresponding cursor position followed by a colon. When you selected line N and this line has the result CWFoo Bar configured the result string is CWN:Foo Bar.

-Q STR, --quit-result=STR

Sets the result string on quit. Default is the empty string.

-V, --version

Displays version identification string.

Use these to browse through the selection list.

  CURSOR-UP ..... Move cursor one line up
  CURSOR-DOWN ... Move cursor one line down
  PAGE-UP ....... Move cursor one page up
  PAGE-DOWN ..... Move cursor one page down
  g ............. Goto first line
  G ............. Goto last line

Use these to select one line and exit in standard mode or one or more lines in multi-line mode.

  RETURN ........ Select line and exit
  CURSOR-RIGHT .. Select line and exit
  SPACE ......... Select line and stay (multi-line mode only)
  C ............. Clear current marks (multi-line mode only)

Note: the CWC keystroke is a Debian extension to iSelect 1.2.0, which has been reported to Ralf S. Engelschall.

Use these to quit iSelect or to show its help and version page.

  q ............. Quit (exit without selection)
  CURSOR-LEFT ... Quit (exit without selection)
  h ............. Help Page
  v ............. Version Page

As an example we present a real-life situation where iSelect can enhance an existing functionality. We define two Bash functions (for your $HOME/.bashrc file) which enhance the built-in cd command of the shell.

 #   database scan for enhanced cd command
 cds () {
     (cd $HOME; 
      find . -type d -print |\
      sed -e "s;^\.;$HOME;" |\
      sort -u >$HOME/.cdpaths ) &
 }

 #   definition of the enhanced cd command
 cd () {
     if [ -d $1 ]; then
          builtin cd $1
     else
          builtin cd `egrep "/$1[^/]*$" $HOME/.cdpaths |\
                      iselect -a -Q $1 -n "chdir" \
                              -t "Change Directory to..."` 
     fi
     PS1="\u@\h:$PWD\n:> "
 }

This new cd command is compatible with Bashs built-in variant for the case where the specified directory actually exists. When it doesn't, the original cd would immediately give an error (assuming we have no CDPATH variable defined). Here this enhanced version tries harder. First it searches for such a directory in a previously built (via cds) $HOME/.cdpaths files. When no line was found, iSelect just returns the given directory as the default result and cd then fails as usual with an error message. When only one directory was found, iSelect directly results this particular line to cd. And only when more then one directory was found, iSelect opens its Curses-based selection screen and lets the user choose interactively between those directories. The chosen directory is then finally given to cd.

For more useful examples on how to use iSelect, see the contrib/ directory of the iSelect distribution tarball.

  Ralf S. Engelschall
  rse@engelschall.com
  www.engelschall.com

  iSelect Home: http://www.engelschall.com/sw/iselect/