One way:
Sample file

    $ cat file
    Cygwin
    Unix
    Linux
    Solaris
    AIX

Using sed, replacing the next line after the pattern &#39;Unix&#39; with &#39;hi&#39;:

    $ sed &#39;/Unix/{n;s/.*/hi/}&#39; file
    Cygwin
    Unix
    hi
    Solaris
    AIX


For your specific question:

    $ sed &#39;/&lt;key&gt;ConnectionString&lt;\/key&gt;/{n;s/&lt;string&gt;.*&lt;\/string&gt;/&lt;string&gt;NEW STRING&lt;\/string&gt;/}&#39; your_file
    &lt;key&gt;ConnectionString&lt;/key&gt;
    &lt;string&gt;NEW STRING&lt;/string&gt;



This might work for you (GNU sed):

&lt;!-- language: sh --&gt;

    sed &#39;/&lt;key&gt;ConnectionString&lt;\/key&gt;/!b;n;c&lt;string&gt;changed_value&lt;/string&gt;&#39; file

`!b` negates the previous address (regexp) and breaks out of any processing, ending the sed commands, `n` prints the current line and then reads the next into the pattern space, `c` changes the current line to the string following the command.

It works. Additionaly is interested to mention that if you write,

    sed &#39;/&lt;key&gt;ConnectionString&lt;\/key&gt;/!b;n;n;c&lt;string&gt;changed_value&lt;/string&gt;&#39; file

Note the two n&#39;s, it replaces after two lines and so forth.



I am getting the &quot;No space left on device&quot; error for pretty much anything i try to do. Even using tab to autocomplete a command!

but when i do df -h i get:

    ubuntu@ip-10-0-2-108:~$ df -h
    Filesystem      Size  Used Avail Use% Mounted on
    /dev/xvda1       99G  6.5G   88G   7% /
    udev            3.7G  8.0K  3.7G   1% /dev
    tmpfs           1.5G  184K  1.5G   1% /run
    none            5.0M     0  5.0M   0% /run/lock
    none            3.7G     0  3.7G   0% /run/shm
    none            100M     0  100M   0% /run/user
    /dev/xvdb       414G  199M  393G   1% /mnt
    overflow        1.0M  1.0M     0 100% /tmp

which to me looks like there is tons of space. df -i also looks similar:

    ubuntu@ip-10-0-2-108:~$ df -i
    Filesystem       Inodes IUsed    IFree IUse% Mounted on
    /dev/xvda1      6553600 94227  6459373    2% /
    udev             951353   393   950960    1% /dev
    tmpfs            953649   274   953375    1% /run
    none             953649     3   953646    1% /run/lock
    none             953649     1   953648    1% /run/shm
    none             953649     1   953648    1% /run/user
    /dev/xvdb      27525120    11 27525109    1% /mnt
    overflow         953649    12   953637    1% /tmp

I am on an Amazon EC2 ubuntu 12.04 instance.

Here are some examples of the error popping up:

    ubuntu@ip-10-0-2-108:~$ sudo crontab -e
    /tmp/crontab.RvYjrR/crontab: No space left on device

    ubuntu@ip-10-0-2-108:~$ ls /va (hit tab for autocomplete)
    
    -bash: cannot create temp file for here-document: No space left on device
    -bash: cannot create temp file for here-document: No space left on device

however the server seems to be running and everything seems to be working.
what on earth is going on??




ubuntu &quot;No space left on device&quot; but there is tons of space

I wrote a stored procedure to import and transform data from one database to another. Each import would take a single company ID and import all data related to this company.

To help with the transformation step I use temporary tables. As part of script review, I was told to use table variables rather than temporary tables.
The reviewer claims that if we run two different imports at the same time, the temporary table would be shared and corrupt the import.

---
**Questions:**

 * Is it true that the temporary table would be shared if we run two different imports at the same time?
 * Does each call to `EXEC` create a new scope?

---
Here is a contrived example of the script.

&lt;!-- language: lang-sql --&gt;

    CREATE PROC [dbo].[ImportCompany]
    (
    	@CompanyId AS INTEGER
    )
    AS
    EXEC [dbo].[ImportAddress] @CompanyId = @CompanyId 
    --Import other data
    
    CREATE PROC [dbo].[ImportAddress]
    (
    	@CompanyId AS INTEGER
    )
    AS
    	CREATE TABLE #Companies (OldAddress NVARCHAR(128), NewAddress NVARCHAR(128))
    	INSERT INTO #Companies(OldAddress, NewAddress)
    	SELECT
    		Address as OldAddress,
    		&#39;Transformed &#39; + Address as NewAddress
    	FROM
    		[OldDb].[dbo].[Addresses]
    	WHERE
    		CompanyId = @CompanyId
    
        --Do stuff with the transformed data

    	DROP TABLE #Companies

    EXEC [dbo].[ImportCompany] @CompanyId = 12345

Scope of temporary tables in SQL Server

I&#39;m trying to find a line in a file and replace the next line with a specific value. I tried sed, but it seems to not like the \n. How else can this be done?

The file looks like this:

    &lt;key&gt;ConnectionString&lt;/key&gt;
    &lt;string&gt;anything_could_be_here&lt;/string&gt;

And I&#39;d like to change it to this

    &lt;key&gt;ConnectionString&lt;/key&gt;
    &lt;string&gt;changed_value&lt;/string&gt;

Here&#39;s what I tried:

    sed -i &#39;&#39; &quot;s/&lt;key&gt;ConnectionString&lt;\/key&gt;\n&lt;string&gt;&lt;\/string&gt;/&lt;key&gt;ConnectionString&lt;\/key&gt;\n&lt;string&gt;replaced_text&lt;\/string&gt;/g&quot; /path/to/file

find matching text and replace next line

I'm trying to find a line in a file and replace the next line with a specific value. I tried sed, but it seems to not like the \n. How else can this be done?
The file looks like this:
<pre><code class="hljs language-php-template">&#x3C;key>ConnectionString&#x3C;/key>
&#x3C;string>anything_could_be_here&#x3C;/string>
</code></pre>
And I'd like to change it to this
<pre><code class="hljs language-php-template">&#x3C;key>ConnectionString&#x3C;/key>
&#x3C;string>changed_value&#x3C;/string>
</code></pre>
Here's what I tried:
<pre><code class="hljs language-php-template">sed -i '' "s/&#x3C;key>ConnectionString&#x3C;\/key>\n&#x3C;string>&#x3C;\/string>/&#x3C;key>ConnectionString&#x3C;\/key>\n&#x3C;string>replaced_text&#x3C;\/string>/g" /path/to/file
</code></pre>

I have the following command in the part of a backup shell script:

    tar -cjf site1.bz2 /var/www/site1/

When I list the contents of the archive, I get:

    tar -tf site1.bz2
    var/www/site1/style.css
    var/www/site1/index.html
    var/www/site1/page2.html
    var/www/site1/page3.html
    var/www/site1/images/img1.png
    var/www/site1/images/img2.png
    var/www/site1/subdir/index.html

But I would like to remove the part `/var/www/site1` from directory and file names within the archive, in order to simplify extraction and avoid useless constant directory structure. Never know, in case I would extract backuped websites in a place where web data weren&#39;t stored under `/var/www`.

For the example above, I would like to have :

    tar -tf site1.bz2
    style.css
    index.html
    page2.html
    page3.html
    images/img1.png
    images/img2.png
    subdir/index.html

So, that when I extract, files are extracted in the current directory and I don&#39;t need to move extracted files afterwards, and so that sub-directory structures is preserved.

There are already many questions about tar and backuping in `stackoverflow` and at other places on the web, but most of them ask for dropping the entire sub-directory structure (flattening), or just add or remove the initial / in the names (I don&#39;t know what it changes exactly when extracting), but no more.

After having read some of the solutions found here and there as well as the manual, I tried :

    tar -cjf site1.bz2 -C . /var/www/site1/
    tar -cjf site1.bz2 -C / /var/www/site1/
    tar -cjf site1.bz2 -C /var/www/site1/ /var/www/site1/
    tar -cjf site1.bz2 --strip-components=3 /var/www/site1/

But none of them worked the way I want. Some do nothing, some others don&#39;t archive sub-directories anymore.

It&#39;s inside a backup shell script launched by a Cron, so I don&#39;t know well, which user runs it, what is the path and the current directory, so always writing absolute path is required for everything, and would prefer not changing current directory to avoid breaking something further in the script (because it doesn&#39;t only backup websites, but also databases, then send all that to FTP etc.)

How to achieve this?

Have I just misunderstood how the option -C works?



Tar a directory, but don&#39;t store full absolute paths in the archive

I’m following in [Generating SSH Keys][1], it says

&gt; ```sudo apt-get install xclip```
&gt;
 Downloads and installs xclip. If you don&#39;t have `apt-get`, you might need to use another installer (like `yum`)  
&gt;
&gt; ```xclip -sel clip &lt; ~/.ssh/id_rsa.pub```
&gt;
  Copies the contents of the id_rsa.pub file to your clipboard

But after I run`xclip -sel clip &lt; ~/.ssh/id_rsa.pub` I get `Error: Can&#39;t open display: (null)`
What is the problem? I googled around but found nothing about it

  [1]: https://help.github.com/articles/generating-ssh-keys#platform-linux

Error: Can&#39;t open display: (null) when using Xclip to copy ssh public key

What is the difference between assigning to a variable like `var=foo` and using let like `let var=foo`? Or cases like `var=${var}bar` and `let var+=bar`? What are the advantages and disadvantages of each approach?

Bash: let statement vs assignment

I do not know the service&#39;s name, but would like to stop the service by checking its status. 

For example, if I want to check if the [PostgreSQL][1] service is running or not, but I don&#39;t know the service&#39;s name, then how could I check its status?

I know the command to check the status if the service name is known.

  [1]: http://en.wikipedia.org/wiki/PostgreSQL


How to check if a service that I don&#39;t know the name of is running on Ubuntu

I want to extract the value pair from a key-value pair syntax but I can not.   
Example I tried:  

    echo employee_id=1234 | sed &#39;s/employee_id=$[0-9]+$/\1/g&#39;

But this gives `employee_id=1234` and not `1234` which is actually the capture group.  

What am I doing wrong here? I also tried:

    echo employee_id=1234| egrep -o employee_id=([0-9]+)

but no success.

Can not extract the capture group with either sed or grep

I have `abc.sh`:

    exec $ROOT/Subsystem/xyz.sh

On a Unix box, if I print `echo $HOME` then I get `/HOME/COM/FILE`.

I want to replace `$ROOT` with `$HOME` using sed.

Expected Output: 

    exec /HOME/COM/FILE/Subsystem/xyz.sh

I tried, but I&#39;m not getting the expected output:

    sed  &#39;s/$ROOT/&quot;${HOME}&quot;/g&#39; abc.sh &gt; abc.sh.1

----

Addition: 

If I have `abc.sh`

    exec $ROOT/Subsystem/xyz.sh $ROOT/ystem/xyz1.sh

then with 

    sed &quot;s|\$INSTALLROOT/|${INSTALLROOT}|&quot; abc.sh

it is only replacing first `$ROOT`, i.e., output is coming as 

    exec /HOME/COM/FILE/Subsystem/xyz.sh $ROOT/ystem/xyz1.sh

How to use variables in a command in sed?

I&#39;m trying to replace a string in a Makefile on Mac OS X for cross-compiling to iOS. The string has embedded double quotes. The command is:

    sed -i &quot;&quot; &#39;s|&quot;iphoneos-cross&quot;,&quot;llvm-gcc:-O3|&quot;iphoneos-cross&quot;,&quot;clang:-Os|g&#39; Configure

And the error is:

    sed: RE error: illegal byte sequence

I&#39;ve tried escaping the double quotes, commas, dashes, and colons with no joy. For example:

    sed -i &quot;&quot; &#39;s|\&quot;iphoneos-cross\&quot;\,\&quot;llvm-gcc\:\-O3|\&quot;iphoneos-cross\&quot;\,\&quot;clang\:\-Os|g&#39; Configure

I&#39;m having a heck of a time debugging the issue. Does anyone know how to get `sed` to print the position of the illegal byte sequence? Or does anyone know what the illegal byte sequence is?

RE error: illegal byte sequence on Mac OS X

I have a new Ubuntu 12.04 VPS. I am trying to write a setup script that completes an entire LAMP installation. Where I am having trouble is appending a line to the `/etc/hosts` file. My current hosts file looks like this:

    127.0.0.1       localhost Venus

    # The following lines are desirable for IPv6 capable hosts
    ::1     ip6-localhost ip6-loopback
    fe00::0 ip6-localnet
    ff00::0 ip6-mcastprefix
    ff02::1 ip6-allnodes
    ff02::2 ip6-allrouters

I would like it to look like this:

    127.0.0.1       localhost Venus
    192.241.xx.xx  venus.example.com venus

    # The following lines are desirable for IPv6 capable hosts
    ::1     ip6-localhost ip6-loopback
    fe00::0 ip6-localnet
    ff00::0 ip6-mcastprefix
    ff02::1 ip6-allnodes
    ff02::2 ip6-allrouters

I have tried a variety of `sed` commands using the append (`\a`) command. For some reason Ubuntu either just echoes the contents of the `hosts` file in terminal or does nothing at all. How would I properly inject the second line into the file with a bash script?

Append line to /etc/hosts file with shell script

Being forced to use CVS for a current client and the address changed for the remote repo. The only way I can find to change the remote address in my local code is a recursive search and replace.

However, with the sed command I&#39;d expect to work:

    find ./ -type f -exec sed -i &quot;s/192.168.20.1/new.domain.com/&quot; {} \;

I get an error for every file:

    sed: 1: &quot;.//file/path ...&quot;: invalid command code .

I&#39;ve tried to escape the periods in the sed match/replacement but that doesn&#39;t solve anything.

Content Type	Original Author	Original Content on Stackoverflow
Question	bswinnerton	View Question on Stackoverflow
Solution 1 - Linux	Guru	View Answer on Stackoverflow
Solution 2 - Linux	potong	View Answer on Stackoverflow
Solution 3 - Linux	Rubén Colomina	View Answer on Stackoverflow

find matching text and replace next line

Linux Problem Overview

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Scope of temporary tables in SQL Server

ubuntu "No space left on device" but there is tons of space

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