lookupvar
str = lookupvar(varname);
pwd = lookupvar("PWD");
if (*name != '/' && (pwd = lookupvar("PWD")) != NULL && *pwd != '\0') {
home = lookupvar("HOME");
val = lookupvar(var);
term = lookupvar("TERM");
if ((shinit = lookupvar("ENV")) != NULL && *shinit != '\0') {
value = lookupvar(varname);
pwd = lookupvar("PWD");
home = lookupvar("HOME");
char *lookupvar(const char *);