This happens when a piped program (e.g. grep) closes the read pipe before the previous program is finished writing the whole page. In curl “url” | grep -qs foo, as soon as grep has what it wants it will close the read stream from curl. cURL doesn’t expect this and emits the “Failed writing body” … Read more
You can set the pipefail shell option option on to get the behavior you want. From the Bash Reference Manual: The exit status of a pipeline is the exit status of the last command in the pipeline, unless the pipefail option is enabled (see The Set Builtin). If pipefail is enabled, the pipeline’s return status … Read more
You need to supply a filter as an argument. To pass the JSON through unmodified other than the pretty printing jq provides by default, use the identity filter .: curl -s https://api.github.com/users/octocat/repos | jq ‘.’ | cat
Use IFS= read var << EOF $(foo) EOF You can trick read into accepting from a pipe like this: echo “hello world” | { read test; echo test=$test; } or even write a function like this: read_from_pipe() { read “$@” <&0; } But there’s no point – your variable assignments may not last! A pipeline … Read more
Piping to another process (Although this WON’T accomplish what you said you are trying to do): command1 | command2 This will send the output of command1 as the input of command2 -exec on a find (this will do what you are wanting to do — but is specific to find) find . -name ‘*.foo’ -exec … Read more
Here is a solution that works at on any Unix / Linux implementation, assuming it cares to follow the POSIX standard. It works on some non Unix environments like cygwin too. echo ‘ee’ | tee /dev/tty | foo Reference: The Open Group Base Specifications Issue 7 IEEE Std 1003.1, 2013 Edition, §10.1: /dev/tty Associated with … Read more
In a pure POSIX shell, if [ -t 1 ] ; then echo terminal; else echo “not a terminal”; fi returns “terminal”, because the output is sent to your terminal, whereas (if [ -t 1 ] ; then echo terminal; else echo “not a terminal”; fi) | cat returns “not a terminal”, because the output … Read more
If you have Python version >= 2.7, you can use subprocess.check_output which basically does exactly what you want (it returns standard output as string). Simple example (linux version, see note): import subprocess print subprocess.check_output([“ping”, “-c”, “1”, “8.8.8.8”]) Note that the ping command is using linux notation (-c for count). If you try this on Windows … Read more
To use a pipe with the subprocess module, you have to pass shell=True. However, this isn’t really advisable for various reasons, not least of which is security. Instead, create the ps and grep processes separately, and pipe the output from one into the other, like so: ps = subprocess.Popen((‘ps’, ‘-A’), stdout=subprocess.PIPE) output = subprocess.check_output((‘grep’, ‘process_name’), … Read more
There is an internal Bash variable called $PIPESTATUS; it’s an array that holds the exit status of each command in your last foreground pipeline of commands. <command> | tee out.txt ; test ${PIPESTATUS[0]} -eq 0 Or another alternative which also works with other shells (like zsh) would be to enable pipefail: set -o pipefail … … Read more