Can someone help me out? I'm too tired to think straight. Is there an easy/short way to get all BUT the last n lines of a text file/input? All I can think of is reversing the input line order and tail +n or something like that. FYI the input is not very big. Kevin
if doing it sort of manually, wc -l to get a line count, then head (total - n) for the rest? On 2015-03-04 12:36 PM, Kevin McGregor wrote:
Can someone help me out? I'm too tired to think straight.
Is there an easy/short way to get all BUT the last n lines of a text file/input? All I can think of is reversing the input line order and tail +n or something like that. FYI the input is not very big.
Kevin
_______________________________________________ Roundtable mailing list Roundtable@muug.mb.ca http://www.muug.mb.ca/mailman/listinfo/roundtable
Like Tim said, you first have to know how many lines exist in the file before you can do anything other than stream processing. On moderately-sized inputs, "wc -l" works reasonably well. On large inputs, there's no way to do this efficiently unless you're willing to sacrifice accuracy. F=filename L=$(wc -l $F) head -n $(( $L - num_of_ignored_lines )) -Adam On March 4, 2015 2:36:24 PM CST, Kevin McGregor <kevin.a.mcgregor@gmail.com> wrote:
Can someone help me out? I'm too tired to think straight.
Is there an easy/short way to get all BUT the last n lines of a text file/input? All I can think of is reversing the input line order and tail +n or something like that. FYI the input is not very big.
Kevin
------------------------------------------------------------------------
_______________________________________________ Roundtable mailing list Roundtable@muug.mb.ca http://www.muug.mb.ca/mailman/listinfo/roundtable
-- Sent from my Android device with K-9 Mail. Please excuse my brevity.
Idea from thread below: | awk '{if(a) print a;a=b;b=$0}' Note that you might want to include a little more logic if you want blanklines in there.. This doesn't store all of it in a file or in ram. http://askubuntu.com/questions/475694/awk-command-to-print-all-the-lines-exc... On 2015-03-04 3:33 PM, Adam Thompson wrote:
Like Tim said, you first have to know how many lines exist in the file before you can do anything other than stream processing. On moderately-sized inputs, "wc -l" works reasonably well. On large inputs, there's no way to do this efficiently unless you're willing to sacrifice accuracy.
F=filename L=$(wc -l $F) head -n $(( $L - num_of_ignored_lines ))
-Adam
On March 4, 2015 2:36:24 PM CST, Kevin McGregor <kevin.a.mcgregor@gmail.com> wrote:
Can someone help me out? I'm too tired to think straight.
Is there an easy/short way to get all BUT the last n lines of a text file/input? All I can think of is reversing the input line order and tail +n or something like that. FYI the input is not very big.
Kevin
------------------------------------------------------------------------
Roundtable mailing list Roundtable@muug.mb.ca http://www.muug.mb.ca/mailman/listinfo/roundtable
-- Sent from my Android device with K-9 Mail. Please excuse my brevity.
_______________________________________________ Roundtable mailing list Roundtable@muug.mb.ca http://www.muug.mb.ca/mailman/listinfo/roundtable
man head head --lines=-5 textfile.txt all but the last 5 lines. On Wed, Mar 4, 2015 at 3:49 PM, Robert Keizer <robert@keizer.ca> wrote:
Idea from thread below:
| awk '{if(a) print a;a=b;b=$0}'
Note that you might want to include a little more logic if you want blanklines in there.. This doesn't store all of it in a file or in ram.
http://askubuntu.com/questions/475694/awk-command-to-print-all-the-lines-exc...
On 2015-03-04 3:33 PM, Adam Thompson wrote:
Like Tim said, you first have to know how many lines exist in the file before you can do anything other than stream processing. On moderately-sized inputs, "wc -l" works reasonably well. On large inputs, there's no way to do this efficiently unless you're willing to sacrifice accuracy.
F=filename L=$(wc -l $F) head -n $(( $L - num_of_ignored_lines ))
-Adam
On March 4, 2015 2:36:24 PM CST, Kevin McGregor <kevin.a.mcgregor@gmail.com> wrote:
Can someone help me out? I'm too tired to think straight.
Is there an easy/short way to get all BUT the last n lines of a text file/input? All I can think of is reversing the input line order and tail +n or something like that. FYI the input is not very big.
Kevin
------------------------------------------------------------------------
Roundtable mailing list Roundtable@muug.mb.ca http://www.muug.mb.ca/mailman/listinfo/roundtable
-- Sent from my Android device with K-9 Mail. Please excuse my brevity.
_______________________________________________ Roundtable mailing list Roundtable@muug.mb.ca http://www.muug.mb.ca/mailman/listinfo/roundtable
_______________________________________________ Roundtable mailing list Roundtable@muug.mb.ca http://www.muug.mb.ca/mailman/listinfo/roundtable
-- John Lange www.johnlange.ca
Sometimes, it's the simple solutions that elude us... :) But wait! Compatibility alert! Using a negative line count on head(1) is a GNU extension, and likely won't work with more "traditional" UNIX implementations. Gilbert On 04/03/2015 4:10 PM, John Lange wrote:
man head
head --lines=-5 textfile.txt
all but the last 5 lines.
On Wed, Mar 4, 2015 at 3:49 PM, Robert Keizer <robert@keizer.ca <mailto:robert@keizer.ca>> wrote:
Idea from thread below:
| awk '{if(a) print a;a=b;b=$0}'
Note that you might want to include a little more logic if you want blanklines in there.. This doesn't store all of it in a file or in ram.
http://askubuntu.com/questions/475694/awk-command-to-print-all-the-lines-exc...
On 2015-03-04 3:33 PM, Adam Thompson wrote: > Like Tim said, you first have to know how many lines exist in the file > before you can do anything other than stream processing. > On moderately-sized inputs, "wc -l" works reasonably well. On large > inputs, there's no way to do this efficiently unless you're willing to > sacrifice accuracy. > > F=filename > L=$(wc -l $F) > head -n $(( $L - num_of_ignored_lines )) > > -Adam > > On March 4, 2015 2:36:24 PM CST, Kevin McGregor > <kevin.a.mcgregor@gmail.com <mailto:kevin.a.mcgregor@gmail.com>> wrote: > > Can someone help me out? I'm too tired to think straight. > > Is there an easy/short way to get all BUT the last n lines of a > text file/input? All I can think of is reversing the input line > order and tail +n or something like that. FYI the input is not > very big. > > Kevin
-- Gilbert E. Detillieux E-mail: <gedetil@muug.mb.ca> Manitoba UNIX User Group Web: http://www.muug.mb.ca/ PO Box 130 St-Boniface Phone: (204)474-8161 Winnipeg MB CANADA R2H 3B4 Fax: (204)474-7609
Duh -- forgot to mention it's for Solaris 11.2. head on Solaris is not GNU. OTOH, it has 'tac'! So I guess I'll use that with tail +n (or something like that). Thanks, guys! On Wed, Mar 4, 2015 at 4:19 PM, Gilbert E. Detillieux < gedetil@cs.umanitoba.ca> wrote:
Sometimes, it's the simple solutions that elude us... :)
But wait! Compatibility alert! Using a negative line count on head(1) is a GNU extension, and likely won't work with more "traditional" UNIX implementations.
Gilbert
On 04/03/2015 4:10 PM, John Lange wrote:
man head
head --lines=-5 textfile.txt
all but the last 5 lines.
On Wed, Mar 4, 2015 at 3:49 PM, Robert Keizer <robert@keizer.ca <mailto:robert@keizer.ca>> wrote:
Idea from thread below:
| awk '{if(a) print a;a=b;b=$0}'
Note that you might want to include a little more logic if you want blanklines in there.. This doesn't store all of it in a file or in ram.
http://askubuntu.com/questions/475694/awk-command- to-print-all-the-lines-except-the-last-three-lines
On 2015-03-04 3:33 PM, Adam Thompson wrote: > Like Tim said, you first have to know how many lines exist in the file > before you can do anything other than stream processing. > On moderately-sized inputs, "wc -l" works reasonably well. On large > inputs, there's no way to do this efficiently unless you're willing to > sacrifice accuracy. > > F=filename > L=$(wc -l $F) > head -n $(( $L - num_of_ignored_lines )) > > -Adam > > On March 4, 2015 2:36:24 PM CST, Kevin McGregor > <kevin.a.mcgregor@gmail.com <mailto:kevin.a.mcgregor@gmail.com>> wrote: > > Can someone help me out? I'm too tired to think straight. > > Is there an easy/short way to get all BUT the last n lines of a > text file/input? All I can think of is reversing the input line > order and tail +n or something like that. FYI the input is not > very big. > > Kevin
-- Gilbert E. Detillieux E-mail: <gedetil@muug.mb.ca> Manitoba UNIX User Group Web: http://www.muug.mb.ca/ PO Box 130 St-Boniface Phone: (204)474-8161 Winnipeg MB CANADA R2H 3B4 Fax: (204)474-7609
_______________________________________________ Roundtable mailing list Roundtable@muug.mb.ca http://www.muug.mb.ca/mailman/listinfo/roundtable
participants (6)
-
Adam Thompson -
Gilbert E. Detillieux -
John Lange -
Kevin McGregor -
Robert Keizer -
Tim Lavoie