I am obviously missing something basic here but can someone explain to me what is wrong with the first statement, which returns nothing? $ history | grep ^su $ history | grep su 2997 su -l 3024 su -l 3050 su -l 3054 su -l Thanks, -- *** E-Mail is NOT a SECURE channel *** James B. Byrne mailto:ByrneJB at Harte-Lyne.ca Harte & Lyne Limited http://www.harte-lyne.ca 9 Brockley Drive vox: +1 905 561 1241 Hamilton, Ontario fax: +1 905 561 0757 Canada L8E 3C3
there are numbers at the start of the line? e.g. your regex is actually something more like "^[0-9]+ su" and depending on your unix variant (e.g. not a linux, possibly) you really mean egrep and not grep (although to a centos list, yes they're likely actually the same, but it still might be worth noting) On Mon, Sep 16, 2013 at 12:27 PM, James B. Byrne <byrnejb at harte-lyne.ca>wrote:> I am obviously missing something basic here but can someone explain to me > what > is wrong with the first statement, which returns nothing? > > $ history | grep ^su > $ history | grep su > 2997 su -l > 3024 su -l > 3050 su -l > 3054 su -l > > Thanks, > > -- > *** E-Mail is NOT a SECURE channel *** > James B. Byrne mailto:ByrneJB at Harte-Lyne.ca > Harte & Lyne Limited http://www.harte-lyne.ca > 9 Brockley Drive vox: +1 905 561 1241 > Hamilton, Ontario fax: +1 905 561 0757 > Canada L8E 3C3 > > _______________________________________________ > CentOS mailing list > CentOS at centos.org > http://lists.centos.org/mailman/listinfo/centos >-- Even the Magic 8 ball has an opinion on email clients: Outlook not so good.
On Mon, Sep 16, 2013 at 11:27 AM, James B. Byrne <byrnejb at harte-lyne.ca> wrote:> I am obviously missing something basic here but can someone explain to me what > is wrong with the first statement, which returns nothing? > > $ history | grep ^su > $ history | grep su > 2997 su -l > 3024 su -l > 3050 su -l > 3054 su -lSomeone else already pointed out the line numbers, but if you are doing this interactively, you probably really want bash's internal 'search-history' operations (usually control-r for reverse-search-history, but there are a bunch of options). -- Les Mikesell lesmikesell at gmail.com
On Mon Sep 16 16:34:31 UTC 2013, zGreenfelder zgreenfelder at gmail.com wrote:>On Mon, Sep 16, 2013 at 12:27 PM, > James B. Byrne <byrnejb at harte-lyne.ca>wrote: >> I am obviously missing something basic here but can someone explain >> to me what is wrong with the first statement, which returns nothing? >> >> $ history | grep ^su >> $ history | grep su >> 2997 su -l >> 3024 su -l >> 3050 su -l >> 3054 su -l> there are numbers at the start of the line?Duh! Thanks. I could not see the forest for the trees I guess. I ended up with the following as I wanted a visual scan of all variants not just the most recent: history | cut -f1-3 -d " " --complement | grep ^su This is in the bash shell on CentOS-6.4. -- *** E-Mail is NOT a SECURE channel *** James B. Byrne mailto:ByrneJB at Harte-Lyne.ca Harte & Lyne Limited http://www.harte-lyne.ca 9 Brockley Drive vox: +1 905 561 1241 Hamilton, Ontario fax: +1 905 561 0757 Canada L8E 3C3