Re: make

>    cat x | grep y

>>> man quote:
>>>         GNU grep -E attempts to support traditional usage by assuming
>>> that { is
>>>         not   special  if  it  would  be  the  start  of  an  invalid
>>> interval
>>>         specification.  For example, the command grep -E '{1' searches
>>> for  the
>>>         two-character  string  {1  instead  of  reporting a syntax error
>>> in the
>>>         regular expression.  POSIX allows this behavior as  an
>>> extension,  but
>>>         portable scripts should avoid it.

>>>     you guys are so helpful! Thanks.

>>>     :-)~MIKE~(-:

>>>     On Sun, Aug 24, 2014 at 7:40 PM, Jon Kettenhofen <subs@kexsof.com
>>>     <mailto:subs@kexsof.com>> wrote:

>>>         I like visible proofs, so here's a test I ran:
>>>         (terminal output was as is shown)

>>>         [jon@localhost ~]$ rm temp
>>>         [jon@localhost ~]$ echo >>temp
>>>         [jon@localhost ~]$ echo $?
>>>         0
>>>         [jon@localhost ~]$ cat temp

>>>         [jon@localhost ~]$ echo >>temp 2>&1
>>>         [jon@localhost ~]$ echo $?
>>>         0
>>>         [jon@localhost ~]$ cat temp

>>>         [jon@localhost ~]$

>>>         as you can see, no errors and the single ">" did not erase the
>>>         file when used in this manner.  So Mike's script should work as
>>>         intended
>>>         at least if there is no stderr output.

>>>         but suppose there was an error? (apologizing for the length of
>>> ...)

>>>         [jon@localhost ~]$ echo "echo" >test
>>>         [jon@localhost ~]$ echo "ls temp2" >>test
>>>         [jon@localhost ~]$ # test ls of non-existent file
>>>         [jon@localhost ~]$ ls temp2
>>>         ls: cannot access temp2: No such file or directory
>>>         [jon@localhost ~]$ echo $?
>>>         2
>>>         [jon@localhost ~]$ # see, we get both an error and stderr
>>> message
>>>         [jon@localhost ~]$ # so
>>>         [jon@localhost ~]$ mv test test.sh
>>>         [jon@localhost ~]$ chgmod +x test.sh
>>>         bash: chgmod: command not found...
>>>         [jon@localhost ~]$ chmod +x test.sh
>>>         [jon@localhost ~]$ # i'm not perfect!
>>>         [jon@localhost ~]$ rm temp
>>>         [jon@localhost ~]$ ./test.sh >>temp
>>>         ls: cannot access temp2: No such file or directory
>>>         [jon@localhost ~]$ echo $?
>>>         2
>>>         [jon@localhost ~]$ cat temp

>>>         [jon@localhost ~]$ ./test.sh >>temp 2>&1
>>>         [jon@localhost ~]$ echo $?
>>>         2
>>>         [jon@localhost ~]$ cat temp

>>>         ls: cannot access temp2: No such file or directory
>>>         [jon@localhost ~]$

>>>         as you can see, Mike's script will work as he apparently
>>> intended,
>>>         providing he's using a modern version of bash.

>>>         On 08/24/2014 09:56 PM, James Mcphee wrote:

>>>             you've said make, append stdout (default file descriptor 1)
>>>             to file
>>>             make.fail, assign stderr (default filedescriptor 2) the same
>>>             filedescriptor as stdout.  So...  If the intent was to have
>>>             both stderr
>>>             and stdout append make.fail, then it is correct.

>>>             On Sun, Aug 24, 2014 at 6:06 PM, Michael Havens
>>>             <bmike1@gmail.com <mailto:bmike1@gmail.com>
>>>             <mailto:bmike1@gmail.com <mailto:bmike1@gmail.com>>> wrote:

>>>                  what I really need to know is will this:

>>>                      make>>make.fail 2>&1

>>>                  send stderr and stdout to the file 'make.fail' or did I
>>>             write it
>>>                  incorrectly?

>>>                  :-)~MIKE~(-:

>>>                  On Sun, Aug 24, 2014 at 2:56 PM, Brian Cluff
>>>             <brian@snaptek.com <mailto:brian@snaptek.com>
>>>                  <mailto:brian@snaptek.com <mailto:brian@snaptek.com>>>

>>>             wrote:

>>>                      the > will delete any file that it points at even
>>>             if the command
>>>                      doesn't actually output anything.  It will even
>>>             delete the file
>>>                      is the command doesn't exist like if you type grep
>>>             as gerp
>>>                       >file, file will still be created/overwritten.

>>>                      If you want to make sure that your command doesn't
>>>             overwrite any
>>>                      existing files you have to set the noclobber option
>>>             like:
>>>                      $ set -o noclobber

>>>                      A good trick to know:
>>>                      You can use the > to delete the contents of a file
>>>             without
>>>                      having to delete and recreate the file by simply
>>>             doing this:
>>>                      $ >yourfile

>>>                      Brian Cluff

>>>                      On 08/24/2014 02:36 PM, Michael Havens wrote:

>>>                          I have a question about redirections:

>>>                               make>>make.fail 2>&1

>>>                          tells it make and then to send (>) stderr (2)
>>>             to stdout (1)
>>>                          and also to
>>>                          send stdout that way also (&1). finally all of
>>>             that gets
>>>                          sent to a file
>>>                          named make.fail (>>). Isn't '>>' actually
>>>             'append' whereas
>>>                          '>' would
>>>                          work just as well so long as the file didn't
>>>             already exist?
>>>                          If the file
>>>                          did exist would I get an error or would the
>>>             file be overwritten?
>>>                          :-)~MIKE~(-:

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>>>             --
>>>             James McPhee
>>>             jmcphe@gmail.com <mailto:jmcphe@gmail.com>
>>>             <mailto:jmcphe@gmail.com <mailto:jmcphe@gmail.com>>

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