/usr/share/doc/ruby1.9.1-examples/examples/curses/view2.rb is in ruby1.9.1-examples 1.9.3.0-1ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 | #!/usr/bin/ruby1.9.1
require "curses"
# A curses based file viewer
class FileViewer
# Create a new fileviewer, and view the file.
def initialize(filename)
@data_lines = []
@screen = nil
@top = nil
init_curses
load_file(filename)
interact
end
# Perform the curses setup
def init_curses
# signal(SIGINT, finish)
Curses.init_screen
Curses.nonl
Curses.cbreak
Curses.noecho
@screen = Curses.stdscr
@screen.scrollok(true)
#$screen.keypad(true)
end
# Load the file into memory, and put
# the first part on the curses display.
def load_file(filename)
fp = open(filename, "r") do |fp|
# slurp the file
fp.each_line { |l|
@data_lines.push(l.chop)
}
end
@top = 0
@data_lines[0..@screen.maxy-1].each_with_index{|line, idx|
@screen.setpos(idx, 0)
@screen.addstr(line)
}
@screen.setpos(0,0)
@screen.refresh
rescue
raise "cannot open file '#{filename}' for reading"
end
# Scroll the display up by one line
def scroll_up
if( @top > 0 )
@screen.scrl(-1)
@top -= 1
str = @data_lines[@top]
if( str )
@screen.setpos(0, 0)
@screen.addstr(str)
end
return true
else
return false
end
end
# Scroll the display down by one line
def scroll_down
if( @top + @screen.maxy < @data_lines.length )
@screen.scrl(1)
@top += 1
str = @data_lines[@top + @screen.maxy - 1]
if( str )
@screen.setpos(@screen.maxy - 1, 0)
@screen.addstr(str)
end
return true
else
return false
end
end
# Allow the user to interact with the display.
# This uses EMACS-like keybindings, and also
# vi-like keybindings as well, except that left
# and right move to the beginning and end of the
# file, respectively.
def interact
while true
result = true
c = Curses.getch
case c
when Curses::KEY_DOWN, Curses::KEY_CTRL_N, ?j
result = scroll_down
when Curses::KEY_UP, Curses::KEY_CTRL_P, ?k
result = scroll_up
when Curses::KEY_NPAGE, ?\s # white space
for i in 0..(@screen.maxy - 2)
if( ! scroll_down )
if( i == 0 )
result = false
end
break
end
end
when Curses::KEY_PPAGE
for i in 0..(@screen.maxy - 2)
if( ! scroll_up )
if( i == 0 )
result = false
end
break
end
end
when Curses::KEY_LEFT, Curses::KEY_CTRL_T, ?h
while( scroll_up )
end
when Curses::KEY_RIGHT, Curses::KEY_CTRL_B, ?l
while( scroll_down )
end
when ?q
break
else
@screen.setpos(0,0)
@screen.addstr("[unknown key `#{Curses.keyname(c)}'=#{c}] ")
end
if( !result )
Curses.beep
end
@screen.setpos(0,0)
end
Curses.close_screen
end
end
# If we are being run as a main program...
if __FILE__ == $0
if ARGV.size != 1 then
printf("usage: #{$0} file\n");
exit
end
viewer = FileViewer.new(ARGV[0])
end
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