If you're searching a long file to find a particular word or name, or you're running a program like ls -l and you want to filter some lines, here's a quick way to narrow down the search. As an example, say your phone file has 20,000 lines like these:
Smith, Nancy:MFG:50 Park Place:Huntsville:(205)234-5678
and you want to find someone named Nancy. When you see more information, you know you can find which of the Nancys she is:
grep Nancy phones...150 lines of names...
Use the C shell'sand to cut out lines you don't want. For example, about a third of the Nancys are in Huntsville, and you know she doesn't work there:
!! | sed -e /Huntsville/dgrep Nancy phones | sed -e /Huntsville/d ...100 lines of names...
The shell shows the command it's executing: the previous command (
piped to sed, which deletes lines in the grep
output that have the word Huntsville.
Okay. You know Nancy doesn't work in the MFG or SLS groups, so delete those lines, too:
!! -e /MFG/d -e /SLS/dgrep Nancy phones | sed -e /Huntsville/d -e /MFG/d -e /SLS/d ...20 lines of names...
!! to repeat the previous command line, and adding
more sed expressions, until the list gets short enough.
The same thing works for other commands - when you're hunting
output, for example, and you want to skip lines with
uulog | sed -e /SUCCEEDED/d -e /OK/d...
If the matching pattern has anything but letters and numbers in it, you'll have to understandand sed . Most times, though, this quick-and-dirty way works just fine.