Before setting $PS1, __git_ps1() uses a command substitution to redirect the output from a printf into a variable. Spare the overhead of fork()ing a subshell by using 'printf -v <var>' to directly assign the output to that variable. zsh's printf doesn't support the '-v <var>' option, so stick with the command substitution when under zsh. Signed-off-by: SZEDER Gábor <szeder@ira.uka.de>