3
votes
1answer
22 views

Using pv(1) to limit rsync speed

I'm trying to use pv rather than rsync's builtin --bwlimit to limit the bandwidth of an rsync transfer because --bwlimit is implemented in an eventually-consistent way, and my transfers are so short ...
5
votes
1answer
59 views

How many ways does Unix feign files?

I know Unix filesystem sometimes has things that appear to be files but are not actually files. The files in dev actually point to devices. Its also possible to created named pipes which also appear ...
0
votes
1answer
190 views

How can I pipe the output of *all* entered shell commands into another? (e.g. pipe everything into 'lolcat')

Good Afternoon, (OS X user) I am specifically trying to pipe the output of every shell command I type into the ruby gem 'lolcat' (which makes the output to the terminal rainbow colored). Is there a ...
1
vote
2answers
537 views

Using Piping with cat and less to concatenate 2 files

I'm fairly new to Unix commands and I just have a simple question. One exercise I'm working on wants me to use piping along with cat and less to concatenate 2 directories (in this case /etc/passwd ...
5
votes
1answer
250 views

cat-ing a file to a unix pipe causes Matlab to freeze

I've created a named pipe on Debian using mkfifo pipe.in. I want to write to this pipe from Matlab. To do this, I use the following matlab command: unix( 'cat <myfile> > pipe.in' ) ...
0
votes
1answer
985 views

Unix pipe: find | ln -s

I'm trying to symlink some php files using the following command: find `pwd` -name "*.php" | ln -s * /home/frankv/www/bietroboter.de/symlinks However, all the symlinks are broken because the little ...
0
votes
1answer
501 views

How to find the last match of a string in a bunch of files

I have a bunch of files, I'd like to find the last match of a string in each of them. grep text *.file gives me all the matches not the last ones. ls *.file | xargs grep text | tail -n 1 gives me ...
21
votes
6answers
2k views

What is the general consensus on “Useless use of cat”?

When I pipe multiple unix commands such as grep, sed, tr etc. I tend to specify the input file that is being processed using cat. So something like cat file | grep ... | awk ... | sed ... . But ...
2
votes
1answer
1k views

How long do FIFOs (named pipes) stay “open” for?

For example, I have a script that writes the time to a pipe in /etc/pipe. It writes continuously in a while true loop. How long will the data in the pipe be available for reading? If I only decide to ...
1
vote
2answers
2k views

How to feed grep output into scp?

I have a file where each line is a file name. Content of the file: file1 file2 file3 ... I then run a grep command to get a subset of the list of the file names. How do I feed the output of the ...
2
votes
1answer
84 views

Which is better: using flags, or pipes?

As with many things in the *nix world, there is more than one way to generate .tar.gz files. Typically, I use the following: tar zcf /path/to/dir.tar.gz /path/to/dir However, I have seen the ...
10
votes
5answers
5k views

What is a “pipe” and how can it be “broken”?

I've gotten the "broken pipe" error from Xcode one time too many. I'm now curious to know exactly what a pipe is. What is the concept of a "pipe" and how can it be "broken"?
9
votes
7answers
5k views

Advantages of cat'ing file and piping to grep

Are there any additional advantages of cat'ing a file and piping it to grep, besides convenience? The convenience being that, when I retrieve commands such as those below from my history, the cursor ...
4
votes
5answers
673 views

commands executing in piping in UNIX

when I write a command $ echo date then it prints "date" as it is i.e it doesn't run date program. But when I write $ echo date | wc then correct answer is produced as if date was run. How ...
3
votes
1answer
641 views

Unix commandline to repeat command with pipes

I want to write a script that will repeat a commandline that usually contains pipes ./myscript.sh ls -lart |grep ^d And in myscript.sh I do a bunch of stuff, and then want to execute ls -lart |grep ...