Measure pipe throughput in the shell
There is a shell command that allows you to measure how fast the data goes through it, so you can measure the speed of output of commands in a pipe. So instead of:
pipe
What’s the difference between STDIN and arguments passed to command?
I could use the either form to execute the cat method:
Pseudo files for temporary data
I often want to feed relatively short string data (could be several lines though) to commandline programs which accept only input from files (e.g. wdiff) in a repeated fashion. Sure I can create one or more temporary files, save the string there and run the command with the file name as parameter. But it looks to me as if this procedure would be highly inefficient if data is actually written to the disk and also it could harm the disk more than necessary if I repeat this procedure many times, e.g. if I want to feed single lines of long text files to wdiff. Is there a recommended way to circumvent this, say by using pseudo files such as pipes to store the data temporarily without actually writing it to the disk (or writing it only if it exceeds a critical length). Note that wdiff takes two arguments and, as far as I understand it will not be possible to feed the data doing something like wdiff <"text".
Performance differences between pipelines and process substitution
I tend to use pipelines in my bash scripts over process substitution in most situations, especially in cases of using multiple sets of commands as it seems more readable to do ... | ... | ... over ... < <(... < <(...)).
How to make reading and writing the same file in the same pipeline always “fail”?
Say I have the following script:
Completely buffer command output before piping to another command?
Is there a way to only execute a command after another is done without a temp file?
I have one longer running command and another command that formats the output and sends it to a HTTP server using curl.
If i just execute commandA | commandB, commandB will start curl, connect to the server and start sending data. Because commandAtakes so long, the HTTP server will timeout.
I can do what I want with commandA > /tmp/file && commandB </tmp/file && rm -f /tmp/file
Are Linux utilities smart when running piped commands?
I was just running a few commands in a terminal and I started wondering, does Unix/Linux take shortcuts when running piped commands?
Piping STDERR vs. STDOUT
According to “Linux: The Complete Reference 6th Edition” (pg. 44), you can pipe only STDERR using the |& redirection symbols.
Why can’t certain programs (like readlink) take input from a pipe?
I have a symbolic link to a script in my $PATH whose file I wanted to edit. I forgot the filepath, so I tried to do the following:
Is there a command like “tee” that limits the file size and treats the output file like a fixed-size queue?
Does there exist a command where one can do something like: