Shell Programming and Scripting

Hi,

What does this line do

Code:

 grep -E 'ORA-' $LIN_TOP/log/status.log > /dev/null 2>&1

Does this check in status.log and in std out, stderr also.?

Thanks

Hi,
grep search pattern "ORA-" in status.log file and redirect the stdout to /dev/null

Code:

2>&1

mean redirect stderr to stdout,in your case stdout is already redirected to (output of grep command) /dev/null, so stderr is directed to /dev/null

Thanks
Pravin

Thanks for reply pravin.

If the output is redirected to /dev/null then it will not exist right, as it is temp file.

Full code below

Code:

if ( grep -E 'ORA-'  $LIN_TOP/log/status.log  > /dev/null 2>&1 ) ; then
  print "Error found in daily job step4"
  fi

/dev/null is not a temp file. The redirects throw away all output written standard output and all diagnostics written to standard error, but the grep command also returns an exit status that indicates whether it found one or more lines containing the string "ORA-", found no lines containing that string, or had trouble reading the input file.

With the given if statement, this sequence of commands will write "Error found in daily job step4" and a newline character to standard output if one or more lines in the specified file contain the string "ORA-".