Running backtick with gdb reveals that the crash is caused by the `memcpy' at line 63 of src/libexecline/el_modifs_and_exec.c
Thanks for doing my work for me :D (these are the bugs I usually catch before release, but, laziness.) The latest execline git head should fix it. If it works for you, I'll cut the 2.9.5.1 release. -- Laurent