How to find out if the line exists in textfile

[darton]

Hello!
I made a script that shows me a line of a textfile. For example with "!showline 2" my bot shows the second line of the file. But how can I find out if this line exists, e.g. if the file only has one line?

[caesar]

Simple, open the file and use a loop to incr a variabile with the number of lines, then close the file and return the number of lines.

Code: Select all

proc count:lines {file} {
  if {![llength $file]} return
  set lines 0
  set f [open $file r]
  while {[gets $f foo]>-1} { 
    incr lines
  }
  close $f
  return $lines
}

Not tested but should work.

[De Kus]

well, I assume when the script can post a specific line, it probably uses an '[lindex $listoflines [expr {$arg + 1}]]' statement. To check in such a case, a simple

Code: Select all

if {[llength $listoflines] < $arg} {
#  no such line
} else {
#  ok, lets print
}

could be used