asn@magrathea:~> strace -s 128 -o kdesu.log -t -f kdesu -c wireshark-qt kdesu(9188)/kdesu (kdelibs) KDESu::PtyProcess::exec: [ /home/abuild/rpmbuild/BUILD/kdelibs-4.14.1/kdesu/process.cpp : 293 ] Running "/usr/bin/su" kdesu(9188)/kdesu (kdelibs) KDESu::SuProcess::ConverseSU: [ /home/abuild/rpmbuild/BUILD/kdelibs-4.14.1/kdesu/su.cpp : 259 ] Read line "Password: " kdesu(9188)/kdesu (kdelibs) KDESu::PtyProcess::exec: [ /home/abuild/rpmbuild/BUILD/kdelibs-4.14.1/kdesu/process.cpp : 293 ] Running "/usr/bin/su" kdesu(9188)/kdesu (kdelibs) KDESu::SuProcess::ConverseSU: [ /home/abuild/rpmbuild/BUILD/kdelibs-4.14.1/kdesu/su.cpp : 259 ] Read line "Password: " kdesu(9188)/kdesu (kdelibs) KDESu::PtyProcess::WaitSlave: [ /home/abuild/rpmbuild/BUILD/kdelibs-4.14.1/kdesu/process.cpp : 379 ] Child pid 9201 kdesu(9188)/kdesu (kdelibs) KDESu::SuProcess::ConverseSU: [ /home/abuild/rpmbuild/BUILD/kdelibs-4.14.1/kdesu/su.cpp : 259 ] Read line "" kdesu(9188)/kdesu (kdelibs) KDESu::SuProcess::ConverseSU: [ /home/abuild/rpmbuild/BUILD/kdelibs-4.14.1/kdesu/su.cpp : 259 ] Read line "su: " kdesu(9188)/kdesu (kdelibs) KDESu::SuProcess::ConverseSU: [ /home/abuild/rpmbuild/BUILD/kdelibs-4.14.1/kdesu/su.cpp : 259 ] Read line "Authentication failure" kdesu(9188)/kdesu (kdelibs) KDESu::PtyProcess::exec: [ /home/abuild/rpmbuild/BUILD/kdelibs-4.14.1/kdesu/process.cpp : 293 ] Running "/usr/bin/su" kdesu(9188)/kdesu (kdelibs) KDESu::SuProcess::ConverseSU: [ /home/abuild/rpmbuild/BUILD/kdelibs-4.14.1/kdesu/su.cpp : 259 ] Read line "Password: " kdesu(9188)/kdesu (kdelibs) KDESu::PtyProcess::WaitSlave: [ /home/abuild/rpmbuild/BUILD/kdelibs-4.14.1/kdesu/process.cpp : 379 ] Child pid 9213 kdesu(9188)/kdesu (kdelibs) KDESu::SuProcess::ConverseSU: [ /home/abuild/rpmbuild/BUILD/kdelibs-4.14.1/kdesu/su.cpp : 259 ] Read line "" kdesu(9188)/kdesu (kdelibs) KDESu::SuProcess::ConverseSU: [ /home/abuild/rpmbuild/BUILD/kdelibs-4.14.1/kdesu/su.cpp : 259 ] Read line "su: " kdesu(9188)/kdesu (kdelibs) KDESu::SuProcess::ConverseSU: [ /home/abuild/rpmbuild/BUILD/kdelibs-4.14.1/kdesu/su.cpp : 259 ] Read line "Authentication failure" kdesu(9188)/kdesu (kdelibs) KDESu::PtyProcess::exec: [ /home/abuild/rpmbuild/BUILD/kdelibs-4.14.1/kdesu/process.cpp : 293 ] Running "/usr/bin/su" kdesu(9188)/kdesu (kdelibs) KDESu::SuProcess::ConverseSU: [ /home/abuild/rpmbuild/BUILD/kdelibs-4.14.1/kdesu/su.cpp : 259 ] Read line "Password: " kdesu(9188)/kdesu (kdelibs) KDESu::PtyProcess::WaitSlave: [ /home/abuild/rpmbuild/BUILD/kdelibs-4.14.1/kdesu/process.cpp : 379 ] Child pid 9224 kdesu(9188)/kdesu (kdelibs) KDESu::SuProcess::ConverseSU: [ /home/abuild/rpmbuild/BUILD/kdelibs-4.14.1/kdesu/su.cpp : 259 ] Read line "" kdesu(9188)/kdesu (kdelibs) KDESu::SuProcess::ConverseSU: [ /home/abuild/rpmbuild/BUILD/kdelibs-4.14.1/kdesu/su.cpp : 259 ] Read line "su: " kdesu(9188)/kdesu (kdelibs) KDESu::SuProcess::ConverseSU: [ /home/abuild/rpmbuild/BUILD/kdelibs-4.14.1/kdesu/su.cpp : 259 ] Read line "Authentication failure" asn@magrathea:~> /usr/bin/su root -c /usr/lib64/kde4/libexec/kdesu_stub - Password: kdesu_stub Running su in the commandline works just fine but kdesu fails ...