Linux and Unix Shell Programming

5.8. Combining standard output and error

A neat way of quickly identifying errors is first to direct the output to a file, then direct the errors to another file. Here’s an example.

I have two account files, one that contains information, another that does not (but I do not know this). I want to redirect both files to an output file called accounts.out.

						$ cat account_qtr.doc account_end.doc 1> accounts.out 2> accounts.err
					

Now if I have errors, it will be contained in the file accounts.err.

						$ pg accounts.out 
AVBD 34HJ   OUT 
AVFJ   31KO  OUT 
... 

$ pg accounts.err 
cat: account_end.doc: No such file or directory
					

Without previously knowing if the second file ‘ account_end.doc ’ contained information, using the above redirection for output and errors ...