To append after the pattern: (-i is for in place replace). line1 and line2 are the lines you want to append(or prepend)

    sed -i &#39;/pattern/a \
    line1 \
    line2&#39; inputfile

**Output:**

    #cat inputfile
     pattern
     line1 line2 

To prepend the lines before:

    sed -i &#39;/pattern/i \
    line1 \
    line2&#39; inputfile

**Output:**

    #cat inputfile
     line1 line2 
     pattern
            



The following adds one line after `SearchPattern`.

`sed -i &#39;/SearchPattern/aNew Text&#39; SomeFile.txt`

It inserts `New Text` one line below each line that contains `SearchPattern`.

To add **two lines**, you can use a `\` and enter a newline while typing `New Text`.

POSIX sed requires a `\` and a newline after the `a` sed function. [1]
Specifying the text to append without the newline is a GNU sed extension (as documented in the `sed` info page), so its usage is not as portable.

[1] https://unix.stackexchange.com/questions/52131/sed-on-osx-insert-at-a-certain-line/

Insert a new verse after the given verse in your stanza:

    sed -i &#39;/^lorem ipsum dolor sit amet$/ s:$:\nconsectetur adipiscing elit:&#39; FILE



More portable to use ed; some systems don&#39;t support \n in sed

    printf &quot;/^lorem ipsum dolor sit amet/a\nconsectetur adipiscing elit\n.\nw\nq\n&quot; |\
        /bin/ed $filename


How can I get the path of a file without the file basename?

Something like `/a/path/to/my/file.txt` --&gt; `/a/path/to/my/`

Tried with `.split()` without success. 

Path to a file without basename

In Hadoop when do reduce tasks start? Do they start after a certain percentage (threshold) of mappers complete? If so, is this threshold fixed? What kind of threshold is typically used?

When do reduce tasks start in Hadoop?

I need to edit a good number of files, by inserting a line or multiple lines either right below a unique pattern or above it. Please advise on how to do that using `sed`, `awk`, `perl` (or anything else) in a shell. Thanks! Example:
  
    some text
    lorem ipsum dolor sit amet
    more text

I want to insert `consectetur adipiscing elit` after `lorem ipsum dolor sit amet`, so the output file will look like:

    some text
    lorem ipsum dolor sit amet
    consectetur adipiscing elit
    more text

Using sed, Insert a line above or below the pattern?

<p>I need to edit a good number of files, by inserting a line or multiple lines either right below a unique pattern or above it. Please advise on how to do that using <code>sed</code>, <code>awk</code>, <code>perl</code> (or anything else) in a shell. Thanks! Example:</p>
<pre><code class="hljs language-arduino">some text
lorem ipsum dolor sit amet
more text
</code></pre>
<p>I want to insert <code>consectetur adipiscing elit</code> after <code>lorem ipsum dolor sit amet</code>, so the output file will look like:</p>
<pre><code class="hljs language-arduino">some text
lorem ipsum dolor sit amet
consectetur adipiscing elit
more text
</code></pre>


I have to write a function in bash. The function will take about 7 arguments. I know that I can call a function like this:

To call a function with parameters:

    function_name $arg1 $arg2

And I can refer my parameters like this inside the function:

    function_name () {
       echo &quot;Parameter #1 is $1&quot;
    }

My question is, is there a better way refer to the parameters inside the function? Can I avoid the $1, $2, $3, .... thing and simply use the $arg1, $arg2, ...?

Is there a proper method for this or do I need to re-assign these parameters to some other variables inside the function? E.g.:

    function_name () {
       $ARG1=$1
       echo &quot;Parameter #1 is $ARG1&quot;
    }

Any example would be much appreciated. 

Is there a way to avoid positional arguments in bash?

I have this one-liner:

    get-WmiObject win32_logicaldisk -Computername remotecomputer

and the output is this:

    DeviceID     : A:
    DriveType    : 2
    ProviderName :
    FreeSpace    :
    Size         :
    VolumeName   :

    DeviceID     : C:
    DriveType    : 3
    ProviderName :
    FreeSpace    : 20116508672
    Size         : 42842714112
    VolumeName   :

    DeviceID     : D:
    DriveType    : 5
    ProviderName :
    FreeSpace    :
    Size         :
    VolumeName   :

How do I get `Freespace` and `Size` of `DeviceID` `C:`? I need to extract just these two values with no other informations. I have tried it with `Select` cmdlet, but with no effect.

**Edit:** 
I need to extract the numerical values only and store them in variables. 

How to get disk capacity and free space of remote computer

Is it possible to do following?

 1. Make `git rebase --interactive` to just output standard boilerplate to a file, instead to outputting to a file and opening it in editor.
 2. Let the user edit the file.
 3. Let user re-run `git rebase` with the name of edited file.
 4. Go on with the usual rebase process.

Usecase: scripted rebasing of course. See https://stackoverflow.com/questions/4981061/how-to-re-order-commits-in-git-non-interactively for example.


How do I run git rebase --interactive in non-interactive manner?

I tried this code and it is not working


    #!/bin/sh
    
    #Find the Process ID for syncapp running instance
    
    PID=`ps -ef | grep syncapp &#39;awk {print $2}&#39;`
    
    if [[ -z &quot;$PID&quot; ]] then
    Kill -9 PID
    fi

It is showing a error near awk.

Any suggestions please.


Shell script to capture Process ID and kill it if exist

I am getting an error ./test.sh: line 13: [: missing `]&#39; in the file test.sh
I tried using brackets and other options such as -a or by checking the size of the file p1 but the error is always there and the else statement is always executed irrespective of the input given.I even tried by removing the ; in line 13 but it didn&#39;t help.

test.sh

    #!/bin/bash
    echo &quot;Enter app name&quot;
    read y
    $y &amp;
    top -b -n 1 &gt; topLog.log
    #-w checks for the whole word not and sub string from that word
    grep -w &quot;$y&quot; topLog.log &gt; p1
    #-s option checks if the file p1 is present or not
    if [ -s &quot;p1&quot;];  #line 13
    then 
        echo &quot;Successful &quot;
    else
        echo &quot;Unsuccessful&quot;
    fi
    rm p1

I am new to bash scripting.So if there is any silly mistake please excuse me.


Bash scripting missing &#39;]&#39;

I&#39;ve got data in a large file (280 columns wide, 7 million lines long!) and I need to swap the first two columns. I think I could do this with some kind of awk for loop, to print $2, $1, then a range to the end of the file - but I don&#39;t know how to do the range part, and I can&#39;t print $2, $1, $3...$280! Most of the column swap answers I&#39;ve seen here are specific to small files with a manageable number of columns, so I need something that doesn&#39;t depend on specifying every column number.

The file is tab delimited:

    Affy-id chr 0 pos NA06984 NA06985 NA06986 NA06989

Swap two columns - awk, sed, python, perl

I have a csh script (although I can change languages if it has any relevance) where I have to:

    sed s/AAA/BBB/ file

The problem is that AAA and BBB are paths, and so contain &#39;/&#39;. AAA is fixed, so I can say:

    sed s/\\\/A\\\/A\\\A/BBB/ file

However, BBB is based on variables, including $PWD. How do I escape the &#39;/&#39; in $PWD?

OR is there some other way I should be doing this entirely?

How to replace a path with another path in sed?

I&#39;m trying to refine my code by getting rid of unnecessary white spaces, empty lines, and having parentheses balanced with a space in between them, so:

        int a = 4;
        if ((a==4) ||   (b==5))

        a++   ;

should change to:

        int a = 4;
        if ( (a==4) || (b==5) )
        a++ ;

It does work for the brackets and empty lines. However, it forgets to reduce the multiple spaces to one space:

        int a = 4;
        if ( (a==4) ||   (b==5) )
        a++    ;

Here is my script:

        #!/bin/bash
        # Script to refine code
        #
        filename=read.txt

        sed &#39;s/((/( (/g&#39; $filename &gt; new.txt
        mv new.txt $filename

        sed &#39;s/))/) )/g&#39; $filename &gt; new.txt
        mv new.txt $filename

        sed &#39;s/ +/ /g&#39; $filename &gt; new.txt
        mv new.txt $filename

        sed &#39;/^$/d&#39; $filename &gt; new.txt
        mv new.txt $filename

Also, is there a way to make this script more concise, e.g. removing or reducing the number of commands?

&#39;+&#39; (one or more occurrences) not working with &#39;sed&#39; command

This is what I&#39;m doing (simplified example):

    gsed -i -E &#39;s/^(?!foo)(.*)$/bar\1/&#39; file.txt

I&#39;m trying to put `bar` in front of every line that doesn&#39;t start with `foo`. This is the error:

    gsed: -e expression #1, char 22: Invalid preceding regular expression

What&#39;s wrong?

What&#39;s wrong with my lookahead regex in GNU sed?

I have a file containing a certain number of lines. Each line looks like this:

&lt;!-- language: none --&gt;

    TF_list_to_test10004/Nus_k0.345_t0.1_e0.1.adj:PKMYT1

I would like to remove all before &quot;:&quot; character in order  to retain only PKMYT1 that is a gene name. 
Since I&#39;m not an expert in regex scripting can anyone help me to do this using Unix (sed or awk) or in R?

Remove all text before colon

1. I am using **AWK** script to process some logs.
2. At one place I need to check if the variable value is **null** or **empty** to make some decision.

Any Idea how to achieve the same? 

    awk &#39;
    
    {
        {
           split($i, keyVal, &quot;@&quot;)
           key=keyVal[1];
           val=keyVal[2];
           if(val ~ /^ *$/)
           val=&quot;Y&quot;;
    
        }
    
    }
    
    &#39; File

I have tried with 

    1) if(val == &quot;&quot;)

    2) if(val ~ /^ *$/)

not working in both cases.

How to check if the variable value in AWK script is null or empty?

I have a file which contain following lines:

    /logs/tc0001/tomcat/tomcat7.1/conf/catalina.properties:app.env.server.name = demo.example.com
    /logs/tc0001/tomcat/tomcat7.2/conf/catalina.properties:app.env.server.name = quest.example.com
    /logs/tc0001/tomcat/tomcat7.5/conf/catalina.properties:app.env.server.name = www.example.com

In above output I want to extract 3 fields (Number 2, 4 and the last one `*.example.com`). I am getting the following output:

    cat file | awk -F&#39;/&#39; &#39;{print $3 &quot;\t&quot; $5}&#39;
    tc0001   tomcat7.1
    tc0001   tomcat7.2
    tc0001   tomcat7.5

How do I also extract last field with domain name which is after `&#39;=&#39;`? How do I use `multiple delimiter` to extract field?


Using multiple delimiters in awk

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?

Content Type	Original Author	Original Content on Stackoverflow
Question	vehomzzz	View Question on Stackoverflow
Solution 1 - Scripting	Kamal	View Answer on Stackoverflow
Solution 2 - Scripting	jahroy	View Answer on Stackoverflow
Solution 3 - Scripting	alinsoar	View Answer on Stackoverflow
Solution 4 - Scripting	Chris Rees	View Answer on Stackoverflow

Using sed, Insert a line above or below the pattern?

Scripting Problem Overview

Scripting Solutions

Solution 1 - Scripting

Solution 2 - Scripting

Solution 3 - Scripting

Solution 4 - Scripting

When do reduce tasks start in Hadoop?

Path to a file without basename

Attributions