If your grep supports `-R`, do:

    grep -R &#39;string&#39; dir/

If not, then use `find`:

    find dir/ -type f -exec grep -H &#39;string&#39; {} +

    grep -r -e string directory

`-r` is for recursive; `-e` is optional but its argument specifies the regex to search for.  Interestingly, [POSIX `grep`](http://pubs.opengroup.org/onlinepubs/9699919799/utilities/grep.html) is not required to support `-r` (or `-R`), but &lt;s&gt;I&#39;m practically certain that System V `grep` did, so&lt;/s&gt; in practice they (almost) all do.  Some versions of `grep` support `-R` as well as (or conceivably instead of) `-r`; AFAICT, it means the same thing.

I&#39;m new to the `composer` and I would like to know the difference between `require` and `require-dev`. 
The composer website doesn&#39;t offer a good explanation the difference between these two.  

The part that I don&#39;t get is `Lists packages required for developing this package, or running tests, etc.` from [Composer Official Docs.][1]


  [1]: http://getcomposer.org/doc/04-schema.md#package-links

What&#39;s the difference between require and require-dev?

I am running R on Windows, not as an administrator. When I install a package, the following command doesn&#39;t work:

    &gt; install.packages(&quot;zoo&quot;)
    Installing package(s) into ‘C:/Program Files/R/R-2.15.2/library’
    (as ‘lib’ is unspecified)
    Warning in install.packages :
      &#39;lib = &quot;C:/Program Files/R/R-2.15.2/library&quot;&#39; is not writable

To install a package, I have to specify a library location:

    install.packages(&quot;zoo&quot;, lib=&quot;C:/software/Rpackages&quot;)

To load a package, I also have to specify the library location:

    library(&quot;zoo&quot;, lib.loc=&quot;C:/software/Rpackages&quot;)

All of this is OK, but I wanted to see if I could add `C:/software/Rpackages` to the library path somehow and thus not have to type it each time.

As I searched online, I found that one way to do this is to edit the `Rprofile.site` file and to add the line

    .libPaths(&quot;C:/software/Rpackages&quot;)

However, after doing this, and starting RStudio, this is the output that I get

    &gt; .libPaths()
    [1] &quot;C:/Program Files/R/R-2.15.2/library&quot; &quot;C:/Program Files/RStudio/R/library&quot; 

The `.libPaths` command that I added to the `Rprofile.site` doesn&#39;t seem to have had any effect! Why is this the case? Or more importantly, how can I fix the problem so that I can install and load packages without typing in the library location?

Note: if I start RStudio the `.libPaths()` command seems to work as it is supposed to

    .libPaths(&quot;C:/software/Rpackages&quot;)
    &gt; .libPaths()
    [1] &quot;C:/software/Rpackages&quot;               &quot;C:/Program Files/R/R-2.15.2/library&quot;

Isn&#39;t that strange?

Change R default library path using .libPaths in Rprofile.site fails to work

How to grep a string or a text in a directory and all its subdirectories&#39;files in  LINUX ??

How to grep a string in a directory and all its subdirectories?

<p>How to grep a string or a text in a directory and all its subdirectories'files in  LINUX ??</p>


I want to echo out the filename portion of a find on the linux commandline.  I&#39;ve tried to use the following:

    find www/*.html -type f -exec sh -c &quot;echo $(basename {})&quot; \;

and

    find www/*.html -type f -exec sh -c &quot;echo `basename {}`&quot; \;

and a whole host of other combinations of escaping and quoting various parts of the text.  The result is that the path isn&#39;t stripped:

    www/channel.html
    www/definition.html
    www/empty.html
    www/index.html
    www/privacypolicy.html

Why not?  

Update: While I have a working solution below, I&#39;m still interested in why &quot;basename&quot; doesn&#39;t do what it should do.

Find and basename not playing nicely

I am not sure whether this counts more as an OS issue, but I thought I would ask here in case anyone has some insight from the Python end of things.

I&#39;ve been trying to parallelise a CPU-heavy `for` loop using `joblib`, but I find that instead of each worker process being assigned to a different core, I end up with all of them being assigned to the same core and no performance gain.

Here&#39;s a very trivial example...

	from joblib import Parallel,delayed
	import numpy as np

	def testfunc(data):
		# some very boneheaded CPU work
		for nn in xrange(1000):
			for ii in data[0,:]:
				for jj in data[1,:]:
					ii*jj

	def run(niter=10):
		data = (np.random.randn(2,100) for ii in xrange(niter))
		pool = Parallel(n_jobs=-1,verbose=1,pre_dispatch=&#39;all&#39;)
		results = pool(delayed(testfunc)(dd) for dd in data)

	if __name__ == &#39;__main__&#39;:
		run()

...and here&#39;s what I see in `htop` while this script is running:

![htop][1]

I&#39;m running Ubuntu 12.10 (3.5.0-26) on a laptop with 4 cores. Clearly `joblib.Parallel` is spawning separate processes for the different workers, but is there any way that I can make these processes execute on different cores?

  [1]: http://i.stack.imgur.com/thg0Y.png

Why does multiprocessing use only a single core after I import numpy?

I know `ls -t` will list all files by modified time.  But how can I limit these results to only the last *n* files?

How can I list (ls) the 5 last modified files in a directory?

Is it possible to backup a running Docker container? Is the `export` command suitable for doing that?

Backup a running Docker container?

How can I find all zero-byte files in a directory and its subdirectories?

I have done this:
```
#!/bin/bash
lns=`vdir -R *.* $dir| awk &#39;{print $8&quot;\t&quot;$5}&#39;`
temp=&quot;&quot;
for file in $lns; do
    if test $file = &quot;0&quot;; then
        printf $temp&quot;\t&quot;$file&quot;\n&quot;
    fi
    temp=$file
done
```

But, I only get results in the current directory, not subdirs,
and if any file name contains a space then I get only first word followed by tab


Find all zero-byte files in directory and subdirectories

I have the following data in multiple lines:

    foo
    bar
    qux
    zuu
    sdf
    sdfasdf

What I want to do is to convert them to one comma separated line:

    foo,bar,qux,zuu,sdf,sdfasdf


What&#39;s the best unix one-liner to do that?

Turning multiple lines into one comma separated line

Is there any comprehensive list of characters that need to be escaped in Bash? Can it be checked just with `sed`?

In particular, I was checking whether `%` needs to be escaped or not. I tried

    echo &quot;h%h&quot; | sed &#39;s/%/i/g&#39;

and worked fine, without escaping `%`. Does it mean `%` does not need to be escaped? Was this a good way to check the necessity?

And more general: are they the same characters to escape in `shell` and `bash`?

Which characters need to be escaped when using Bash?

I often want to write commands like this (in `zsh`, if it&#39;s relevant):

    find &lt;somebasedirectory&gt; | \
        grep stringinfilenamesIwant | \
        grep -v stringinfilesnamesIdont | \
        xargs dosomecommand

(or more complex combinations of greps)

In recent years `find` has added the `-print0` switch, and xargs has added `-0`, which allow handling of files with spaces in the name in an elegant way by null-terminating filenames instead, allowing for this:

    find &lt;somebasedirectory&gt; -print0 | xargs -0 dosomecommand

However, `grep` (at least the version I have, GNU grep 2.10 on Ubuntu), doesn&#39;t seem to have an equivalent to consume **and** generate null-terminated lines; it has `--null`, but that only seems related to using `-l` to output names when searching in files directly with grep.

Is there an equivalent option or combination of options I can use with grep? Alternatively, is there an easy and elegant way to express my pipe of commands simply using find&#39;s `-regex`, or perhaps Perl?

Is there a grep equivalent for find&#39;s -print0 and xargs&#39;s -0 switches?

I&#39;m trying to run the following command in Terminal: 

    chown -R couchdb:couchdb /usr/local/var/log/couchdb

However, I keep getting this message:

    chown: couchdb: illegal group name

I am using mac osx (mountain lion) and I have command line tools installed. I really don&#39;t know very much about unix, but I&#39;ve been googling the illegal group name error and haven&#39;t turned up anything that would help. What am I overlooking? Any additional resources you think might be helpful also appreciated.

  

chown illegal group name (mac os x)

I&#39;m looking at functions such as `connect()` and `bind()` in C sockets and notice that they take a pointer to a `sockaddr` struct. I&#39;ve been reading and to make your application AF-Independent, it is useful to use the `sockaddr_storage` struct pointer and cast it to a `sockaddr` pointer because of all the extra space it has for larger addresses.

What I am wondering is how functions like `connect()` and `bind()` that ask for a `sockaddr` pointer go about accessing the data from a pointer that points at a larger structure than the one it is expecting. Sure, you pass it the size of the structure you are providing it, but what is the actual syntax that the functions use to get the IP Address off the pointers to larger structures that you have cast to `struct *sockaddr`?

It&#39;s probably because I come from OOP languages, but it seems like kind of a hack and a bit messy.

Reasoning behind C sockets sockaddr and sockaddr_storage

I have a number of lines retrieved from a file after running the [grep][1] command as follows:

    var=`grep xyz abc.txt`

Let’s say I got 10 lines which consists of xyz as a result.

Now I need to process each line I got as a result of the grep command. How do I proceed for this?

  [1]: http://linux.die.net/man/1/grep


How to process each output line in a loop?

When using the Grep command to find a search string in a set of files, how do I dump the results to a text file?

Also is there a switch for the Grep command that provides cleaner results for better readability, such as a line feed between each entry or a way to justify file names and search results?

For instance, a away to change...

```
./file/path: first result
./another/file/path: second result
./a/third/file/path/here: third result
```

to

```
./file/path: first result

./another/file/path: second result

./a/third/file/path/here: third result
```


Output grep results to text file, need cleaner output

I&#39;m writing a shell script, and I&#39;m trying to check if the output of a command contains a certain string. I&#39;m thinking I probably have to use grep, but I&#39;m not sure how. Does anyone know?

Checking if output of a command contains a certain string in a shell script

I&#39;m trying to find a way to scan my entire Linux system for all files containing a specific string of text. Just to clarify, I&#39;m looking for text within the file, not in the file name.

When I was looking up how to do this, I came across this solution twice:

    find / -type f -exec grep -H &#39;text-to-find-here&#39; {} \;

However, it doesn&#39;t work. It seems to display every single file in the system.

Is this close to the proper way to do it? If not, how should I? This ability to find text strings in files would be extraordinarily useful for some programming projects I&#39;m doing.


How do I find all files containing specific text on Linux?

I want to run a python script in a CENTOS server:

    #!/usr/bin/env python
    import socket
    try:    
    	import thread 
    except ImportError:
    	import _thread as thread #Py3K changed it.
    class Polserv(object):
    	def __init__(self):
    		self.numthreads = 0
    		self.tidcount   = 0
    		self.port       = 843
    		self.sock       = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    		self.sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    		self.sock.bind((&#39;100.100.100.100&#39;, self.port))
    		self.sock.listen(5)
    	def run(self):
    		while True:
    			thread.start_new_thread(self.handle, self.sock.accept()) 
    	def handle(self,conn,addr):
    		self.numthreads += 1
    		self.tidcount   += 1
    		tid=self.tidcount
    		while True:
    			data=conn.recv(2048)
    			if not data:
    				conn.close()
    				self.numthreads-=1
    				break
    			#if &quot;&lt;policy-file-request/&gt;\0&quot; in data:
    			conn.sendall(b&quot;&lt;?xml version=&#39;1.0&#39;?&gt;&lt;cross-domain-policy&gt;&lt;allow-access-from domain=&#39;*&#39; to-ports=&#39;*&#39;/&gt;&lt;/cross-domain-policy&gt;&quot;)
    			conn.close()
    			self.numthreads-=1
    			break
    		#conn.sendall(b&quot;[#%d (%d running)] %s&quot; % (tid,self.numthreads,data) )
    Polserv().run()
Im using `$ python flashpolicyd.py` and it works fine... 
The question is: How to keep this script running even after I close the terminal(console)?



How to make Python script run as service?

I am accessing a server running CentOS (linux distribution) with an SSH connection.
Since I can&#39;t always stay logged in, I use &quot;nohup [command] &amp;&quot; to run my programs.

I couldn&#39;t find how to get a list of all the programs I started using nohup.
&quot;jobs&quot; only works out before I log out. After that, if I log back again, the jobs command shows me nothing, but I can see in my log files that my programs are still running.

Is there a way to get a list of all the programs that I started using &quot;nohup&quot; ?

How to get a list of programs running with nohup

I am trying to start httpd server on centos 6. It throws following error :

    [root@machine ~]# service httpd start
    Starting httpd: (13)Permission denied: make_sock: could not bind to address [::]:88
    (13)Permission denied: make_sock: could not bind to address 0.0.0.0:88
    no listening sockets available, shutting down
    Unable to open logs
                                                               [FAILED]

I have also checked for port 88, It is not is use.
I also checked with [semanage][1], but it didn&#39;t help.

Any help will be appreciated.


  [1]: http://rmohan.com/?p=1595

httpd Server not started: (13)Permission denied: make_sock: could not bind to address [::]:88

I have been trying to install php-mcrypt for a while now. Everytime I get the &quot;No package php-mcrypt available.&quot; returned to me. Here&#39;s what I&#39;ve tried:

    root@ip-********** [~]# yum install php-mcrypt --enablerepo=centosplus (&lt;- both with and without this)
    Loaded plugins: fastestmirror
    Loading mirror speeds from cached hostfile
    * base: p3plmirror01.prod.phx3.secureserver.net
    * centosplus: p3plmirror01.prod.phx3.secureserver.net
    * epel: mirrors.solfo.com
    * extras: p3plmirror01.prod.phx3.secureserver.net
    * updates: p3plmirror01.prod.phx3.secureserver.net
    centosplus                                               | 3.5 kB     00:00
    centosplus/primary_db                                    | 746 kB     00:00
    Setting up Install Process
    No package php-mcrypt available.
    Error: Nothing to do

I have made sure to install the EPEL repository. At this point I&#39;m just stumped. I&#39;ve followed EVERY tutorial I&#39;ve found online and get the same error.

Notes: [Go Daddy][1] [VPS][2], [CentOS][3] 6.4 64-bit, mcrypt installed without a hitch, but no php-mcrypt.

  [1]: http://en.wikipedia.org/wiki/Go_Daddy
  [2]: http://en.wikipedia.org/wiki/Virtual_private_server
  [3]: http://en.wikipedia.org/wiki/CentOS


Install php-mcrypt on CentOS 6

I installed Nginx on Centos 6 and I am trying to set up virtual hosts. The problem I am having is that I can&#39;t seem to find the `/etc/nginx/sites-available` directory.

Is there something I need to do in order to create it? I know Nginx is up and running because I can browse to it.

Content Type	Original Author	Original Content on Stackoverflow
Question	Rogers	View Question on Stackoverflow
Solution 1 - Linux	John Kugelman	View Answer on Stackoverflow
Solution 2 - Linux	Jonathan Leffler	View Answer on Stackoverflow

How to grep a string in a directory and all its subdirectories?

Linux Problem Overview

Linux Solutions

Solution 1 - Linux

Solution 2 - Linux

Change R default library path using .libPaths in Rprofile.site fails to work

What's the difference between require and require-dev?

Attributions