Here is a quickie:
(defun c:makelt (/ str file fn exprt)
(setq str (getstring T "\n Enter string for linetype: ")
file (strcat (getvar 'dwgprefix)
(vl-filename-base (getvar 'dwgname))
"_mylt.lin"
)
fn (open file "w")
exprt (getvar 'expert)
)
(write-line (strcat "*" str ", ---" str "---") fn)
(write-line
(strcat "A,0.5,-0.05,[\""
str
"\",STANDARD,S=0.1,R=0.0,X=-0.0,Y=-.05],"
(rtos (* -0.1 (strlen str))2 3)
)
fn
)
(close fn)
(setvar 'expert 5)
(command ".-linetype" "load" "*" file "")
(setvar 'expert exprt)
(vl-file-delete file)
(princ)
)