Forgive me if this is an obvious question, but I've been unable to find the answer. I'd like to add a sh function to configure. I figured I could add something like this to acinclude.m4: foo(){ echo $1 | /usr/bin/sed 's/[A-Za-z]$/&\//g' } then in configure.in I could add something like this: HAHA=`foo "/home/jeff"` AC_SUBST(HAHA) autoconf never complains about this, but HAHA is never defined. Could anyone tell me what I'm missing? TIA, Jeff -- #include <stdio.h> int main(){int a[]={74,117,115,116,32,97,110,111,116,104,101,114,32, \ 67,32,104,97,99,107,101,114,10,0}; int *b=a;while(*b>0)putchar(*b++);}