There is a similar question here: 

https://stackoverflow.com/questions/549810/control-r-reverse-i-search-in-cygwin-bash-how-do-you-reset-the-search

Found another similar question on Super User:


[(reverse-i-search) in Bash][1]

Apparently, both mention &lt;kbd&gt;Ctrl&lt;/kbd&gt;+&lt;kbd&gt;s&lt;/kbd&gt;, which may do the trick.

Hope that helps. I myself am trying to find a piece of code that does the `reverse-i-search` in order to check how it has been implemented exactly.


  [1]: https://superuser.com/questions/159106/reverse-i-search-in-bash

&lt;kbd&gt;CTRL&lt;/kbd&gt; + &lt;kbd&gt;S&lt;/kbd&gt;

...solved it for me AFTER using... 

    stty -ixon

If CTRL+S doesn&#39;t work for you is because according to [Vincenzo Pii&#39;s][1] accepted answer in another related thread: 

&gt; The problem is that this binding, in many terminals, is used by default to send the pause transmission code (`XOF`).

&gt; As in `man stty`:

&gt;&gt;     [-]ixon
        enable XON/XOFF flow control

&gt; So, if you have this option enabled on your terminal (the output of `stty -a` contains `ixon` withouth the `-` sign in front), you cannot use &lt;kbd&gt;CTRL&lt;/kbd&gt;+&lt;kbd&gt;S&lt;/kbd&gt; in the context of *reverse-i-search*.

&gt; To disable it, use the following command:

&gt;     stty -ixon

&gt; And &lt;kbd&gt;CTRL&lt;/kbd&gt;+&lt;kbd&gt;S&lt;/kbd&gt; will give you a `(i-search)` (non reverse).


  [1]: https://stackoverflow.com/questions/17760474/reverse-intelligent-search-reverse-i-search-how-to-get-previous-result?rq=1

Try `delete`, magically worked.

Others point to &lt;kbd&gt;CTRL&lt;/kbd&gt;+&lt;kbd&gt;s&lt;/kbd&gt;, but it doesn&#39;t work for me.

Like some others I am getting this error when I run rake db:migrate in my project or even try most database tasks for my [Ruby on Rails][1] 3.2 applications.

&gt; PGError (could not connect to server: No such file or directory. Is the
&gt; server running locally and accepting connections on Unix domain socket
&gt; &quot;/tmp/.s.PGSQL.5432&quot;?

I installed [PostgreSQL][2] with [Homebrew][3] a long time ago and following an attempted installation of [MongoDB][4] recently my PostgreSQL install has never been the same. I&#39;m running OS&amp;nbsp;X&amp;nbsp;v10.6 Snow&amp;nbsp;Leopard.

What&#39;s wrong and how do I better understand how PostgreSQL is and should be setup on my Mac?

So far (I think) this tells me that PostgreSQL is not running(?).

    ps -aef|grep postgres                                                                                                   (ruby-1.9.2-p320@jct-ana) (develop) ✗
      501 17604 11329   0   0:00.00 ttys001    0:00.00 grep postgres

But does this tell me that PostgreSQL is running?

    ✪ launchctl load -w /usr/local/Cellar/postgresql/9.1.4/homebrew.mxcl.postgresql.plist                                                        (ruby-1.9.2-p136) 
    homebrew.mxcl.postgresql: Already loaded

How do I fix this? what am I not seeing?

PS: `~/Library/LaunchAgents` includes two PostgreSQL .plist files. I am not sure if that&#39;s relevant.

    org.postgresql.postgres.plist
    homebrew.mxcl.postgresql.plist

I tried the following and got a result as below.

**$ psql -p 5432 -h localhost**   

    psql: could not connect to server: Connection refused
    	Is the server running on host &quot;localhost&quot; (127.0.0.1) and accepting
    	TCP/IP connections on port 5432?
    could not connect to server: Connection refused
    	Is the server running on host &quot;localhost&quot; (::1) and accepting
    	TCP/IP connections on port 5432?
    could not connect to server: Connection refused
    	Is the server running on host &quot;localhost&quot; (fe80::1) and accepting
    	TCP/IP connections on port 5432?

I&#39;ve read since that this is occuring because OS&amp;nbsp;X installs its own version of PostgreSQL and Homebrew installs a different version in a different place and the PostgreSQL commands are looking in the /tmp/ directory. You&#39;ll need to search more on Stack&amp;nbsp;Overflow, but basically you symlink PostgreSQL so that anything looking in that tmp path actually finds the real path, if that makes sense.

This is the link where I found a few more things to try, specifically doing the symlink as per above, *https://stackoverflow.com/questions/17240516*. I still wish someone would put together a decent explanation of the concepts behind installing PostgreSQL on OS&amp;nbsp;X and why it&#39;s all so difficult.

Latest insights to help with troubleshooting:
 
    $ which psql // This tells you which PostgreSQL you are using when you run $ psql. 

Then run:

    $ echo $PATH

The key thing to take into account is this:

**Ensure that the path entry for the copy of PostgreSQL you want to run COMES BEFORE the path to the OS&amp;nbsp;X system&#39;s PostgreSQL.**

This is a core requirement which decides which PostgreSQL gets run and is what I&#39;m told leads to most of these issues.

  [1]: http://en.wikipedia.org/wiki/Ruby_on_Rails
  [2]: http://en.wikipedia.org/wiki/PostgreSQL
  [3]: https://en.wikipedia.org/wiki/Homebrew_%28package_management_software%29
  [4]: http://en.wikipedia.org/wiki/MongoDB


PostgreSQL error &#39;Could not connect to server: No such file or directory&#39;

I&#39;ve got:

    words = [&#39;hello&#39;, &#39;world&#39;, &#39;you&#39;, &#39;look&#39;, &#39;nice&#39;]

I want to have:

    &#39;&quot;hello&quot;, &quot;world&quot;, &quot;you&quot;, &quot;look&quot;, &quot;nice&quot;&#39;

What&#39;s the easiest way to do this with Python?

Join a list of strings in python and wrap each string in quotation marks

I use `reverse-i-search` often, and that&#39;s cool. Sometime though when pressing &lt;kbd&gt;CTRL&lt;/kbd&gt;+&lt;kbd&gt;r&lt;/kbd&gt; multiple times, I *pass* the command I am actually looking for. Because &lt;kbd&gt;CTRL&lt;/kbd&gt;+&lt;kbd&gt;r&lt;/kbd&gt; searches backward in history, from newest to oldest, I have to:

 1. cancel,
 2. search again and
 3. stop exactly at the command, without passing it.

While in `reverse-i-search` prompt, is it possible to search forward, i.e. from where I stand to newest. I naively tried &lt;kbd&gt;CTRL&lt;/kbd&gt;+&lt;kbd&gt;Shift&lt;/kbd&gt;+&lt;kbd&gt;r&lt;/kbd&gt;, no luck. I heard about &lt;kbd&gt;CTRL&lt;/kbd&gt;+&lt;kbd&gt;g&lt;/kbd&gt; but this is not what I am expecting here. Anyone has an idea?

How to reverse-i-search back and forth?

I use <code>reverse-i-search</code> often, and that's cool. Sometime though when pressing <kbd>CTRL</kbd>+<kbd>r</kbd> multiple times, I pass the command I am actually looking for. Because <kbd>CTRL</kbd>+<kbd>r</kbd> searches backward in history, from newest to oldest, I have to:
<ol>
<li>cancel,</li>
<li>search again and</li>
<li>stop exactly at the command, without passing it.</li>
</ol>
While in <code>reverse-i-search</code> prompt, is it possible to search forward, i.e. from where I stand to newest. I naively tried <kbd>CTRL</kbd>+<kbd>Shift</kbd>+<kbd>r</kbd>, no luck. I heard about <kbd>CTRL</kbd>+<kbd>g</kbd> but this is not what I am expecting here. Anyone has an idea?

Among the timing functions, `time`, `clock` `getrusage`, `clock_gettime`, `gettimeofday` and `timespec_get`, I want to understand clearly how they are implemented and what are their return values in order to know in which situation I have to use them.

First we need to classify functions returning **wall-clock values** compare to functions returning **process or threads values**. `gettimeofday` returns wall-clock value, `clock_gettime` returns wall-clock value **or** process or threads values depending on the `Clock` parameter passed to it. `getrusage` and `clock` return process values.

Then the second question regards the implementation of these functions and as a consequence, their accuracy. Which hardware or software mechanism does these functions use. 

It seems that `getrusage` uses only the kernel tick (usually 1ms long) and as a consequence can&#39;t be more accurate than the ms. Is it right? 
Then the `getimeofday` function seems to use the most accurate underlying hardware available. As a consequence its accuracy is usually the microsecond (can&#39;t be more because of the API) on recent hardware. 
What about `clock`, the man page speak about &quot;approximation&quot;, what does it mean? 
What about `clock_gettime`, the API is in nanosecond, does it means that it&#39;s able to be so accurate if underlying hardware allows it? What about monotonicity?

Are there any other functions?

Measure time in Linux - time vs clock vs getrusage vs clock_gettime vs gettimeofday vs timespec_get?

I have 2 pages: `xyz.com/a` and `xyz.com/b`. I can only access `xyz.com/b` if and only if I login to `xyz.com/a` first. If accessing `xyz.com/b` without going through the other, I simply get access denied (no redirect to login) via the browser. Once I login at `xyz.com/a`, I can access the other.

My problem is doing this using the curl command. I can login successfully to `xyz.com/a` using curl, but then try `xyx.com/b` and I get access denied.

I use the following:

    curl --user user:pass https://xyz.com/a  #works ok
    curl https://xyz.com/b #doesn&#39;t work

I&#39;ve tried using the second line with &amp; without the user/password part and still doesn&#39;t work. Both pages uses the same CA, so that&#39;s not a problem. Any suggestions? Thanks

CURL to access a page that requires a login from a different page

Whats the syntax for a linux command that hits a URL repeatedly, x number of times. I don&#39;t need to do anything with the data, I just need to replicate hitting refresh 20 times in a browser.

Curl Command to Repeat URL Request

I came across a shell script where the code is 

    for line in $LIST_ARRAY;do
    if [[ $LIST_ARRAY =~ $line ]]
    then
    echo &quot;true&quot;
    ....
    ...
    .
What is the use of `=~` in this case?

Meaning of &quot;=~&quot; operator in shell script

I have a socket server that is supposed to receive UTF-8 valid characters from clients.

The problem is some clients (mainly hackers) are sending all the wrong kind of data over it.

I can easily distinguish the genuine client, but I am logging to files all the data sent so I can analyze it later.

Sometimes I get characters like this `œ` that cause the `UnicodeDecodeError` error.

I need to be able to make the string UTF-8 with or without those characters.


---
**Update:**

For my particular case the socket service was an MTA and thus I only expect to receive ASCII commands such as:

    EHLO example.com
    MAIL FROM: &lt;john.doe@example.com&gt;
    ...

I was logging all of this in JSON.

Then some folks out there without good intentions decided to send all kind of junk.

That is why for my specific case it is perfectly OK to strip the non ASCII characters.

UnicodeDecodeError: &#39;utf8&#39; codec can&#39;t decode byte 0x9c

In one line of bash, how do I return an exit status of 0 when the output of `/usr/local/bin/monit --version` doesn&#39;t contain exactly `5.5` and an exit status of 1 when it does?

How do I test (in one line) if command output contains a certain string?

E.g. on a fresh ubuntu machine, I&#39;ve just run `sudo apt-get git`, and there&#39;s no completion when typing e.g. `git check[tab]`.

I didn&#39;t find anything on http://git-scm.com/docs, but IIRC completion is included in the git package these days and I just need the right entry in my bashrc.

How to configure git bash command line completion?

I searched for noop in bash (:), but was not able to find any good information. What is the exact purpose or use case of this operator?

I tried following and it&#39;s working like this for me:

    [mandy@root]$ a=11
    [mandy@root]$ b=20
    [mandy@root]$ c=30
    [mandy@root]$ echo $a; : echo $b ; echo $c
    10
    30

Please let me know, any use case of this operator in real time or any place where it is mandatory to use it.

What is the use case of noop [:] in bash?

I have this variable:

    A=&quot;Some variable has value abc.123&quot;

I need to extract this value i.e `abc.123`. Is this possible in bash?

How to extract last part of string in bash?

I just recently switched from bash to zsh, however I miss my &lt;kbd&gt;Alt&lt;/kbd&gt;+&lt;kbd&gt;LeftArrowKey&lt;/kbd&gt; and &lt;kbd&gt;Alt&lt;/kbd&gt;+&lt;kbd&gt;RightArrowKey&lt;/kbd&gt; to go back and forth a word at a time.

Right now, if I press &lt;kbd&gt;Alt&lt;/kbd&gt;+&lt;kbd&gt;LeftArrowKey&lt;/kbd&gt; I go back a couple of letters and then I&#39;m stuck. I won&#39;t go any further backwards and it won&#39;t back to the end of the line with &lt;kbd&gt;Alt&lt;/kbd&gt;+&lt;kbd&gt;RightArrowKey&lt;/kbd&gt; as I would expect. I can&#39;t even use the arrow keys to go to the end of the line, only to the second to last. Can&#39;t input new chars on the line either or indeed delete.

How do I get my beloved shortcut back?

I&#39;m on Mac OS X using Terminal if that&#39;s important.

Looking for ALT+LeftArrowKey solution in zsh

I want a way to search in a given text. For that, I use `grep`:

    grep -i &quot;my_regex&quot;

That works. But given the data like this:

    This is the test data
    This is the error data as follows
    . . . 
    . . . .
    . . . . . . 
    . . . . . . . . .
    Error data ends

Once I found the word `error` (using `grep -i error data`), I wish to find the 10 lines that follow the word `error`. So my output should be:

    . . . 
    . . . .
    . . . . . . 
    . . . . . . . . .
    Error data ends

Are there any way to do it?

How do I fetch lines before/after the grep result in bash?

 I&#39;m trying to run a `bash script` on my Ubuntu machine and it is giving me an error: 

&gt; function not found


To test, I created the following script which works fine on my laptop but not on my Desktop.  Any ideas as to why?  My laptop is a mac if that&#39;s relevant.

    #!/bin/bash
    
    function sayIt {   
       echo &quot;hello world&quot;
    }
    
    sayIt

This returns &quot;hello world&quot; on my laptop, but on my Desktop it returns:

&gt; run.sh: 3: function not found  hello world   run.sh: 5: Syntax error:
&gt; &quot;}&quot; unexpected


Bash script error: &quot;function: not found&quot;. Why would this appear?

I have a log file (application.log) which might contain the following string of normal &amp; special characters on multiple lines:

    *^%Q&amp;$*&amp;^@$&amp;*!^@$*&amp;^&amp;^*&amp;^&amp;

I want to search for the line number(s) which contains this special character string.

&lt;!-- language: sh --&gt;

    grep &#39;*^%Q&amp;$*&amp;^@$&amp;*!^@$*&amp;^&amp;^*&amp;^&amp;&#39; application.log

The above command doesn&#39;t return any results.

What would be the correct syntax to get the line numbers?

grep for special characters in Unix

Need to find a way in ElasticSearch to boost the relevance of a document based on a particular value of a field.  Specifically, there is a special field in all my documents where the higher the field value is, the more relevant the doc that contains it should be, regardless of the search.

Consider the following document structure:

    {
        &quot;_all&quot; : {&quot;enabled&quot; : &quot;true&quot;},
        &quot;properties&quot; : {
            &quot;_id&quot;:            {&quot;type&quot; : &quot;string&quot;,  &quot;store&quot; : &quot;yes&quot;, &quot;index&quot; : &quot;not_analyzed&quot;},
            &quot;first_name&quot;:     {&quot;type&quot; : &quot;string&quot;,  &quot;store&quot; : &quot;yes&quot;, &quot;index&quot; : &quot;yes&quot;},
            &quot;last_name&quot;:      {&quot;type&quot; : &quot;string&quot;,  &quot;store&quot; : &quot;yes&quot;, &quot;index&quot; : &quot;yes&quot;},
            &quot;boosting_field&quot;: {&quot;type&quot; : &quot;integer&quot;, &quot;store&quot; : &quot;yes&quot;, &quot;index&quot; : &quot;yes&quot;}
            }
    }


I&#39;d like documents with a higher boosting_field value to be __inherently more relevant__ than those with a lower boosting_field value.  This is just a starting point -- the matching between the query and the other fields will also be taken into account in determining the final relevance score of each doc in the search.  But, __all else being equal, the higher the boosting field, the more relevant the document__.  

Anyone have an idea on how to do this?

Thanks a lot!



ElasticSearch -- boosting relevance based on field value

I have a ArrayList with custom objects. I want to search inside this ArrayList for Strings.

The class for the objects look like this:

    public class Datapoint implements Serializable {
      
      private String stateBased;
      private String name;
      private String priority;
      private String mainNumber;
      private String groupadress;
      private String dptID;
    
      public Datapoint(){
      }
    
      public String getMainNumber() {
        return mainNumber;
      }
    
      public void setMainNumber(String mainNumber) {
        this.mainNumber = mainNumber;
      }
    
      public String getName() {
        return name;
      }
       
      ..and so on

I know how to search for a string in a ArrayList&lt;String&gt; but how to do that in a ArrayList with my custom objects:

    ArrayList&lt;String&gt; searchList = new ArrayList&lt;String&gt;();
    String search = &quot;a&quot;;
    int searchListLength = searchList.size();
    for (int i = 0; i &lt; searchListLength; i++) {
    if (searchList.get(i).contains(search)) {
    //Do whatever you want here
    }
    }


So I want to have a function to search in my ArrayList with for example five objects for all &quot;name&quot; strings. 


Searching in a ArrayList with custom objects for certain strings

I have array with objects.

Something Like this:

    var arr = new Array(
      {x:1, y:2},
      {x:3, y:4}
    );

When I try:

    arr.indexOf({x:1, y:2});

It returns `-1`.

If I have strings or numbers or other type of elements but object, then `indexOf()` works fine.

Does anyone know why and what should I do to search object elements in array?

Of course, I mean the ways except making string hash keys for objects and give it to array...

Why Array.indexOf doesn&#39;t find identical looking objects

I see people are using `any` to gather another list to see if an item exists in a list, but is there a quick way to just do something like this?

    if list.contains(myItem):
        # do something

Content Type	Original Author	Original Content on Stackoverflow
Question	m-ric	View Question on Stackoverflow
Solution 1 - Linux	gdupont	View Answer on Stackoverflow
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Solution 3 - Linux	advisor21	View Answer on Stackoverflow

How to reverse-i-search back and forth?

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Join a list of strings in python and wrap each string in quotation marks

PostgreSQL error 'Could not connect to server: No such file or directory'

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