--- {{{
--- If lain.terminal is a string, e.g. "xterm", then "xterm -e " .. cmd is
--- run. But if lain.terminal is a function, then terminal(cmd) is run.
-
-function helpers.run_in_terminal(cmd)
- if type(terminal) == "function"
- then
- terminal(cmd)
- elseif type(terminal) == "string"
- then
- awful.util.spawn(terminal .. ' -e ' .. cmd)
- end
+-- {{{ File operations
+
+-- see if the file exists and is readable
+function helpers.file_exists(file)
+ local f = io.open(file)
+ if f then
+ local s = f:read()
+ f:close()
+ f = s
+ end
+ return f ~= nil
+end
+
+-- get all lines from a file, returns an empty
+-- list/table if the file does not exist
+function helpers.lines_from(file)
+ if not helpers.file_exists(file) then return {} end
+ local lines = {}
+ for line in io.lines(file) do
+ lines[#lines + 1] = line
+ end
+ return lines
+end
+
+-- match all lines from a file, returns an empty
+-- list/table if the file or match does not exist
+function helpers.lines_match(regexp, file)
+ local lines = {}
+ for index,line in pairs(helpers.lines_from(file)) do
+ if string.match(line, regexp) then
+ lines[index] = line
+ end
+ end
+ return lines
+end
+
+-- get first line of a file, return nil if
+-- the file does not exist
+function helpers.first_line(file)
+ return helpers.lines_from(file)[1]
+end
+
+-- get first non empty line from a file,
+-- returns nil otherwise
+function helpers.first_nonempty_line(file)
+ for k,v in pairs(helpers.lines_from(file)) do
+ if #v then return v end
+ end
+ return nil