zsh redirection with `multios` on does not redirect stdout multiple times
Assume I am in a folder with file a but no b. Then ls a b will have output a goes to stdout and ls: cannot access b: goes to stderr.
Now, in my understanding, with multios on, the command ls a b >output1 2>&1 >output2 will
- redirect stdout to
output1. - copy stderr to stdout, so stderr also goes to
output1
- duplicate stdout to
output2asmultiosis on
So the total effect is that stdout goes to both output1 and output2 while stderr goes to output1
However, I cannot find in output1 the stdout part (the file a). What is wrong with my understanding?
Strangely, If I added another redirection, the multios options will have the effect:
with ls a b >output1 >output2 2>&1 >output3, the stdout goes to output1, output2, output3 at the same time. This conforms to my understanding.
shell zsh io-redirection
asked Dec 31 '18 at 8:29
Liu ShaLiu Sha
596320
add a comment |
Assume I am in a folder with file a but no b. Then ls a b will have output a goes to stdout and ls: cannot access b: goes to stderr.
Now, in my understanding, with multios on, the command ls a b >output1 2>&1 >output2 will
- redirect stdout to
output1. - copy stderr to stdout, so stderr also goes to
output1
- duplicate stdout to
output2asmultiosis on
So the total effect is that stdout goes to both output1 and output2 while stderr goes to output1
However, I cannot find in output1 the stdout part (the file a). What is wrong with my understanding?
Strangely, If I added another redirection, the multios options will have the effect:
with ls a b >output1 >output2 2>&1 >output3, the stdout goes to output1, output2, output3 at the same time. This conforms to my understanding.
shell zsh io-redirection
asked Dec 31 '18 at 8:29
Liu ShaLiu Sha
596320
1
Which zsh version you used? 5.4.2 works for me.
– cuonglm
Jan 11 at 8:30
Yes the version matters. I used 5.0.2. I retried on version 5.4.2 and it works as expected. Thanks.
– Liu Sha
Jan 11 at 8:42
add a comment |
Assume I am in a folder with file a but no b. Then ls a b will have output a goes to stdout and ls: cannot access b: goes to stderr.
Now, in my understanding, with multios on, the command ls a b >output1 2>&1 >output2 will
- redirect stdout to
output1. - copy stderr to stdout, so stderr also goes to
output1
- duplicate stdout to
output2asmultiosis on
So the total effect is that stdout goes to both output1 and output2 while stderr goes to output1
However, I cannot find in output1 the stdout part (the file a). What is wrong with my understanding?
Strangely, If I added another redirection, the multios options will have the effect:
with ls a b >output1 >output2 2>&1 >output3, the stdout goes to output1, output2, output3 at the same time. This conforms to my understanding.
shell zsh io-redirection
asked Dec 31 '18 at 8:29
Liu ShaLiu Sha
596320
Assume I am in a folder with file a but no b. Then ls a b will have output a goes to stdout and ls: cannot access b: goes to stderr.
Now, in my understanding, with multios on, the command ls a b >output1 2>&1 >output2 will
- redirect stdout to
output1. - copy stderr to stdout, so stderr also goes to
output1
- duplicate stdout to
output2asmultiosis on
So the total effect is that stdout goes to both output1 and output2 while stderr goes to output1
However, I cannot find in output1 the stdout part (the file a). What is wrong with my understanding?
Strangely, If I added another redirection, the multios options will have the effect:
with ls a b >output1 >output2 2>&1 >output3, the stdout goes to output1, output2, output3 at the same time. This conforms to my understanding.
shell zsh io-redirection
shell zsh io-redirection
asked Dec 31 '18 at 8:29
Liu ShaLiu Sha
596320
asked Dec 31 '18 at 8:29
Liu ShaLiu Sha
596320
edited Jan 4 at 8:12
Liu Sha
asked Dec 31 '18 at 8:29
Liu ShaLiu Sha
596320
asked Dec 31 '18 at 8:29
Liu ShaLiu Sha
596320
asked Dec 31 '18 at 8:29
Liu ShaLiu Sha
596320
596320
1
Which zsh version you used? 5.4.2 works for me.
– cuonglm
Jan 11 at 8:30
Yes the version matters. I used 5.0.2. I retried on version 5.4.2 and it works as expected. Thanks.
– Liu Sha
Jan 11 at 8:42
add a comment |
1
Which zsh version you used? 5.4.2 works for me.
– cuonglm
Jan 11 at 8:30
Yes the version matters. I used 5.0.2. I retried on version 5.4.2 and it works as expected. Thanks.
– Liu Sha
Jan 11 at 8:42
1
1
Which zsh version you used? 5.4.2 works for me.
– cuonglm
Jan 11 at 8:30
Which zsh version you used? 5.4.2 works for me.
– cuonglm
Jan 11 at 8:30
Yes the version matters. I used 5.0.2. I retried on version 5.4.2 and it works as expected. Thanks.
– Liu Sha
Jan 11 at 8:42
Yes the version matters. I used 5.0.2. I retried on version 5.4.2 and it works as expected. Thanks.
– Liu Sha
Jan 11 at 8:42
add a comment |
0
active
oldest
votes
Your Answer
StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "1"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53985239%2fzsh-redirection-with-multios-on-does-not-redirect-stdout-multiple-times%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
0
active
oldest
votes
0
active
oldest
votes
active
oldest
votes
active
oldest
votes
Thanks for contributing an answer to Stack Overflow!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53985239%2fzsh-redirection-with-multios-on-does-not-redirect-stdout-multiple-times%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
1
Which zsh version you used? 5.4.2 works for me.
– cuonglm
Jan 11 at 8:30
Yes the version matters. I used 5.0.2. I retried on version 5.4.2 and it works as expected. Thanks.
– Liu Sha
Jan 11 at 8:42