title: How to find and remove line from file in Unix?
body: <p>I have one file (for example: test.txt), this file contains some lines and for example one line is: abcd=11
  But it can be for example: abcd=12
  Number is different but abcd= is the same in all case, so could anybody give me command for finding this line and remove it?</p>
  
  <p>I have tried: <code>sed -e \"/$abcd=/d\" /test.txt &gt;/test.txt</code> but it removes all lines from my file and I also have tried: <code>sed -e \"/$abcd=/d\" /test.txt &gt;/testNew.txt</code> but it doesn't delete line from test.txt, it only creates new file (testNew.txt) and in this file it removes my line. But it is not what I want.</p>