title: Use of diff command from tcl script captures error 'child process exited abnormally'
body: <p>In tcl script I am using diff command to compare the files line by line</p>
  
  <pre><code>if {[catch {eval exec "diff /tmp/tECSv2_P_HTTP_XHDR_URL_FUNC_12.itcl /tmp/tempReformat"} results]} {
  
      puts "$results"
  }
  </code></pre>
  
  <p>Output of diff command is obtained properly but it catches error 'child process exited abnormally'</p>
  
  <p>Output: </p>
  
  <pre><code>==&gt;tclsh diffUsingScript
  
  992c992
  &lt;             fail "Redirection is not reflected in css messages"
  ---
  &gt;         fail "Redirection is not reflected in css messages"
  child process exited abnormally
  </code></pre>
  
  <p>So whats going wrong due to which this error is obtained. I want diff operation to be error free in my tcl script </p>