it may come from find . . . | grep which is easier to remember than the method for incorporating the grep verb in a find command. On 08/25/2014 07:51 PM, Michael Havens wrote: > I get it! > > cat x | grep y > > is redundant. did I learn that when it wasn't redundant? if it never has > been redundant I wonder why I thought the pipe was needed? > > :-)~MIKE~(-: > > > On Mon, Aug 25, 2014 at 4:25 PM, Brian Cluff > wrote: > > You'll need to add some single quotes to keep the shell from > interpreting your regex as shell code like this: > > grep -E 'error|fail' {make,install,check}.fail > > Without the single quotes you are telling the system to cat from > your set of files and look for lines with the word error and pipe > that to a program called fail. > > I found that I did have to add the -E even thought the man page says > that in the GNU version of grep the basic and extended regular > expressions are the same... it appears that is not the case in practice. > > Brian Cluff > > > On 08/25/2014 12:56 PM, Michael Havens wrote: > > I have 3 files, make.fail, install.fail, and check.fail. I want > to check > for two words in those files: error and fail. > > would this work? > > cat {make,install,check}.fail | grep -i error|fail > > I was told to put the 'E' option in to grep. Looking at the man > page it > seems that the E option is only useful if I were greping for > something > that begins with a '{'. AM I misreading the man page? > > 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. > > > > :-)~MIKE~(-: > > > On Mon, Aug 25, 2014 at 12:24 PM, Michael Havens > > >> wrote: > > you guys are so helpful! Thanks. > > :-)~MIKE~(-: > > > On Sun, Aug 24, 2014 at 7:40 PM, Jon Kettenhofen > > >> 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 > > > > > >>> 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 > > > > >>> > > 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~(-: > > > > > ------------------------------______--------------------- > PLUG-discuss mailing list - > PLUG-discuss@lists.phxlinux.______org >

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>> > > To subscribe, unsubscribe, or to change your > mail settings: > http://lists.phxlinux.org/____mailman/listinfo/plug-discuss > > > > > > > > > -- > James McPhee > jmcphe@gmail.com > > > > >> > > > > > ------------------------------____--------------------- > PLUG-discuss mailing list - > PLUG-discuss@lists.phxlinux.____org >

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