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charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: DM8PR09MB7095.namprd09.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: b116c66c-e60a-40ac-50a0-08da5785e101 X-MS-Exchange-CrossTenant-originalarrivaltime: 26 Jun 2022 15:09:34.3104 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 14b77578-9773-42d5-8507-251ca2dc2b06 X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH0PR09MB8601 X-OriginatorOrg: ncbi.nlm.nih.gov X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_EF, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE, T_SPF_HELO_PERMERROR autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: cygwin@cygwin.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: General Cygwin discussions and problem reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 26 Jun 2022 15:09:38 -0000 Hi all, An empty PATH element (":xxx" or "xxx::xxx" or "xxx:") is to be considered = as the current directory (from the very first days of Unix). However, Cygwin does not seem to obey the rule. Consider the following simple C program: $ cat hello.c #include #include #include #include int main(int argc, const char* argv[]) { if (argc < 2) { const char* prog =3D strrchr(argv[0], '/'); if (!prog++) prog =3D argv[0]; execlp(prog, prog, "Hello", NULL); // execute just by the program = name perror("exec"); return 1; } printf("%s\n", argv[1]); return 0; } Now compare the execution on Linux and Cygwin: Linux: $ gcc -Wall -o hello hello.c $ hello bash: hello: command not found $ ./hello exec: No such file or directory $ PATH=3D".:$PATH" ./hello Hello $ PATH=3D":$PATH" ./hello Hello $ PATH=3D"${PATH}:" ./hello Hello Cygwin: $ gcc -Wall -o hello hello.c $ hello -bash: hello: command not found $ ./hello exec: No such file or directory $ PATH=3D".:$PATH" ./hello Hello $ PATH=3D":$PATH" ./hello exec: No such file or directory $ PATH=3D"${PATH}:" ./hello exec: No such file or directory As you can see, the execution failed when an empty PATH element was added o= n Cygwin (yet it was perfectly fine on Linux). Anton Lavrentiev Contractor NIH/NLM/NCBI