Hi, We are porting zsh 5.5.1 in AIX. As part of the build, we are running internal test suites by invoking "make check". We are experiencing a hang issue with one of the testcase named " A04redirect.ztst" . Below is the console output (with verbose set to 2 ). ZTST_test: looking for new test ZTST_test: examining line: ZTST_test: examining line: fn() { local foo; read foo; print $foo; } ZTST_getchunk: read code chunk: fn() { local foo; read foo; print $foo; } coproc fn print test output >&p read bar <&p print $bar ZTST_test: examining line: >test output ZTST_getredir: read redir for '>': test output test output ZTST_test: examining line: Running test: '>&p' and '<&p' redirection ZTST_test: expecting status: 0 Input: /tmp/zsh.ztst.2359968/ztst.in, output: /tmp/zsh.ztst.2359968/ztst.out, error: /tmp/zsh.ztst.2359968/ztst.terr test output It hanged at this step. Any help would be great. Thanks Ayappan P