Questions tagged [pipe]
A pipe is an interprocess connection between file descriptors of two processes. A pipe is created with the POSIX pipe() function (from <unistd.h>). Shells create pipes between processes if the "|" symbol is used: "cmd1 | cmd2" directs the output of cmd1 to the input of cmd2. On Windows use CreatePipe(). This mechanism redirects standard input, standard output, and standard error into the calling process in .NET and Java.
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How can I pipe stderr, and not stdout?
I have a program that writes information to stdout and stderr, and I need to process the stderr with grep, leaving stdout aside.
Using a temporary file, one could do it in two steps:
command > /dev/...
user80168
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How can I redirect Windows cmd standard output and standard error to a single file?
I'm trying to redirect all output (standard output and standard error) of a Windows command to a single file:
C:\
cd \
dir 1> a.txt 2> a.txt
Output:
The process cannot access the file because ...
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Pipe output and capture exit status in Bash
I want to execute a long running command in Bash, and both capture its exit status, and tee its output.
So I do this:
command | tee out.txt
ST=$?
The problem is that the variable ST captures the ...
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How to use `subprocess` command with pipes
I want to use subprocess.check_output() with ps -A | grep 'process_name'.
I tried various solutions but so far nothing worked. Can someone guide me how to do it?
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How can I detect if my shell script is running through a pipe?
How do I detect from within a shell script if its standard output is being sent to a terminal or if it's piped to another process?
The case in point: I'd like to add escape codes to colorize output, ...
user111422
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Retrieving the output of subprocess.call() [duplicate]
How can I get the output of a process run using subprocess.call()?
Passing a StringIO.StringIO object to stdout gives this error:
Traceback (most recent call last):
File "<stdin>", ...
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How to pipe stdout while keeping it on screen ? (and not to a output file)
I would like to pipe standard output of a program while keeping it on screen.
With a simple example (echo use here is just for illustration purpose) :
$ echo 'ee' | foo
ee <- the output I would ...
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Read values into a shell variable from a pipe
I am trying to get bash to process data from stdin that gets piped into, but no luck. What I mean is none of the following work:
echo "hello world" | test=($(< /dev/stdin)); echo test=$test
test=
...
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Piping command output to tee but also save exit code of command [duplicate]
I have a shell script in which I wrap a command (mvn clean install), to redirect the output to a logfile.
#!/bin/bash
...
mvn clean install $@ | tee $logfile
echo $? # Does not show the return code ...
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How to pipe list of files returned by find command to cat to view all the files
I am doing a find to get a list of files.
How do I pipe it to another utility like cat so that cat displays the contents of all those files?
Afterwards, I'd use grep on that to search some text in ...
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Why does cURL return error "(23) Failed writing body"?
It works ok as a single tool:
curl "someURL"
curl -o - "someURL"
but it doesn't work in a pipeline:
curl "someURL" | tr -d '\n'
curl -o - "someURL" | tr -d '\n'
it returns:
(23) Failed writing ...
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Piping both stdout and stderr in bash?
It seems that newer versions of bash have the &> operator, which (if I understand correctly), redirects both stdout and stderr to a file (&>> appends to the file instead, as Adrian ...
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How to use `jq` in a shell pipeline?
I can't seem to get jq to behave "normally" in a shell pipeline. For example:
$ curl -s https://api.github.com/users/octocat/repos | jq | cat
results in jq simply printing out its help ...
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What are the parameters for the number Pipe - Angular 2
I have used the number pipe below to limit numbers to two decimal places.
{{ exampleNumber | number : '1.2-2' }}
I was wondering what the logic behind '1.2-2' was? I have played around with these ...
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How to open every file in a folder
I have a python script parse.py, which in the script open a file, say file1, and then do something maybe print out the total number of characters.
filename = 'file1'
f = open(filename, 'r')
content =...
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