kwon@sybil.cs.Buffalo.EDU (Thomas Kwon) (12/09/89)
I'm a novice hacker who is trying to use 'sed' to extract "certain
string" of "certain column" of "certain line" of a result of a "certain
command".
Since that sounds too confusing, here is what I really mean. By typing
'ruptime' at the prompt, I get something like the following :
antares up 21+04:15, 4 users, load 1.36, 1.50, 1.29
castor up 1+05:20, 0 users, load 0.00, 0.00, 0.00
deneb up 42+23:50, 0 users, load 0.00, 0.00, 0.00
gort up 14+14:47, 21 users, load 2.48, 1.77, 1.59
joey up 14+14:42, 2 users, load 0.00, 0.05, 0.26
marvin up 14+15:03, 10 users, load 1.43, 1.34, 1.12
sybil up 14+11:28, 33 users, load 2.83, 2.93, 2.44
wolf up 70+20:41, 0 users, load 1.46, 1.49, 1.28
I want to extract the string "1.34" which is in "column 8" of "line 6"
and set that to a variable. How can this be done?
So far, I've been experimenting with :
set string=`ruptime|sed <Then I got stuck here>`
Any help will be greatly appreciated.
Tom Kwon. *-)jak9213@helios.TAMU.EDU (John Kane) (12/09/89)
In article <14404@eerie.acsu.Buffalo.EDU>, kwon@sybil.cs.Buffalo.EDU (Thomas Kwon) writes: > I'm a novice hacker who is trying to use 'sed' to extract "certain > string" of "certain column" of "certain line" of a result of a "certain > command". > Since that sounds too confusing, here is what I really mean. By typing > 'ruptime' at the prompt, I get something like the following : > > antares up 21+04:15, 4 users, load 1.36, 1.50, 1.29 > castor up 1+05:20, 0 users, load 0.00, 0.00, 0.00 > deneb up 42+23:50, 0 users, load 0.00, 0.00, 0.00 > gort up 14+14:47, 21 users, load 2.48, 1.77, 1.59 > joey up 14+14:42, 2 users, load 0.00, 0.05, 0.26 > marvin up 14+15:03, 10 users, load 1.43, 1.34, 1.12 > sybil up 14+11:28, 33 users, load 2.83, 2.93, 2.44 > wolf up 70+20:41, 0 users, load 1.46, 1.49, 1.28 > > I want to extract the string "1.34" which is in "column 8" of "line 6" > and set that to a variable. How can this be done? > So far, I've been experimenting with : > > set string=`ruptime|sed <Then I got stuck here>` Well, I am not much of a sed user, but I like awk, so how about: set string=`ruptime | awk '$1 == "marvin" {print $8}'` This is fairly short and quick. It looks for a line that has the first field containing the word "marvin" (I assumed that this is what you wanted). It then "prints" the 8th field, in this case "1.34". Nice, short, and sweet. I bet someone could probably do better than this. John Arthur Kane, Systems Analyst, Microcomputer Support and Training Texas A&M University, College Station, TX 77843 (409) 845-9999 jak9213@helios.tamu.edu profs: x043jk@tamvm1.tamu.edu
jdpeek@rodan.acs.syr.edu (Jerry Peek) (12/11/89)
In article <14404@eerie.acsu.Buffalo.EDU> kwon@sybil.cs.Buffalo.EDU (Thomas Kwon) writes: > I'm a novice hacker who is trying to use 'sed' to extract "certain > string" of "certain column" of "certain line" of a result of a "certain > command". > Since that sounds too confusing, here is what I really mean. By typing > 'ruptime' at the prompt, I get something like the following : > > antares up 21+04:15, 4 users, load 1.36, 1.50, 1.29 > castor up 1+05:20, 0 users, load 0.00, 0.00, 0.00 > deneb up 42+23:50, 0 users, load 0.00, 0.00, 0.00 > gort up 14+14:47, 21 users, load 2.48, 1.77, 1.59 > joey up 14+14:42, 2 users, load 0.00, 0.05, 0.26 > marvin up 14+15:03, 10 users, load 1.43, 1.34, 1.12 > sybil up 14+11:28, 33 users, load 2.83, 2.93, 2.44 > wolf up 70+20:41, 0 users, load 1.46, 1.49, 1.28 > > I want to extract the string "1.34" which is in "column 8" of "line 6" > and set that to a variable. How can this be done? It depends on how "ruptime" formats its output -- if a load average number is over 9.99, is there still a leading space? The way I've done it "plays safe" by including all text between the two commas, with the leading space: marvin up 14+15:03, 10 users, load 1.43, 1.34, 1.12 ^^^^^ Here's the line I came up with: set load=`ruptime | sed -n '6s/^.*load[^,]*,\([^,]*\).*/\1/p'` In English, that reads: -n Don't print any line unless I give the "p" command 6s/ On line 6, substitute... ^.*load[^,]*, Everything up to and including the first comma (,) after the word "load" \([^,]*\) Save everything up to but not including the next comma in the tagged field 1 .* The rest of the line /\1/ Replace all that stuff (the entire line) with the contents of tagged field 1 p Print this line If you'd rather have the line that contains the word "marvin" instead of the 6th line, the sed expression should look like this: set load=`ruptime | sed -n '/marvin/s/^.*load[^,]*,\([^,]*\).*/\1/p'` I'm no expert, but I think "sed" is great -- fast and flexible, just cryptic. Maybe Randall and I should have a perl-vs.-sed showdown. :-) :-) --Jerry Peek; Syracuse University Academic Computing Services; Syracuse, NY jdpeek@rodan.acs.syr.edu, JDPEEK@SUNRISE.BITNET +1 315 443-3995
wiml@blake.acs.washington.edu (William Lewis) (12/18/89)
In article <14404@eerie.acsu.Buffalo.EDU> kwon@sybil.cs.Buffalo.EDU (Thomas Kwon) writes: >I want to extract the string "1.34" which is in "column 8" of "line 6" >and set that to a variable. How can this be done? >So far, I've been experimenting with : > > set string=`ruptime|sed <Then I got stuck here>` Alternatively you could use 'cut' to slice out the desired field. Something along the lines of set string=`ruptime|tail +6|head -1|cut -d"," -f4` should work (head and tail to get only that line; cut to get the fourth comma-separated field.) Maybe set string=`ruptime|sed -n6p|cut -d"," -f4` would work better, come to think of it. --- phelliax -- wiml@blake.acs.washington.edu (206)526-5885 Seattle, Washington