Most versions of "tail" have a limited buffer. Mine is 20k. See "man tail" for your system. Thus the "tail -count" syntax is not reliable where the volume of output will exceed the size of the buffer - in fact it will just give you as many lines as it can.
Code:
Here is an example of "tail" going wrong on one of my logs:
tail -200 mylog|wc -l
200
ukh44004 # tail -300 mylog|wc -l
218
tail -400 mylog|wc -l
218
The unix "split" command mentioned earlier will give the correct result for simple text files.
I am trying to do a head on a mainframe file and on doing ti just gives me a blank screen with nothing on it.
however, when i do a tail for the same file...i get a few lines on the screen.
i know tht mainframe files have all the records on one line...does this have to do something with this.... (10 Replies)
hi all,
Please help me to write. How to create the file by getting numbers of rows from orginal file. I tried the following one, doesn't work.
head 50000 file1 >> file1_1
head: cannot open `50000' for reading: No such file or directory
Thank you (2 Replies)
i have to print first n lines of a file. how can i do that without using head command. for some reason i do not want to use Head. is there a way to get that result using awk or sed?.
i an using this on korn shell for AIX
Thanks.. (7 Replies)
Hi, I have the following problem. I have files with one column of data (let's say file1.dat, file2.dat...file6.dat), and I would like to record the first value of the column of each file into another file (let's name it fileall.dat), which would have the the six values, one in each column. I use to... (4 Replies)
Hi there,
my ksh script collects a procstack trace for a particular pid and then greps it by a transaction id to find out the pthread ID:
---------- tid# 1876087 (pthread ID: 4466) ----------
So the pthread ID I want is 4466 in this case, and it is assighed to the variable $pthread.... (4 Replies)
hello everybody,
I have some files in directory.each file contain some data.
my requirement is add the count of each line of file in head of each file.
any advice !!!!!!!! (4 Replies)
Hi All,
I'm a newbie here, I'm just wondering how can i get the head of my file while using awk?
input data:
nik1,nik2,nik3
nik2,nik3,nik4
nik3,nik4,nik5
expected output is:
nik1 because it is in the top and it is in the first delimeted.
i tried awk -F "," '{print $1}' but i... (2 Replies)
Hello,
I am trying to backup the whole folder which contains years of data and huge size, some files are > 10GB. I want keep the exact organization of the folder, except that for bigger file only part of it (say head -50, or simply only the name of the file) will be kept. Then the structure of the... (2 Replies)
Discussion started by: yifangt
2 Replies
LEARN ABOUT PLAN9
tail
TAIL(1) General Commands Manual TAIL(1)NAME
tail - deliver the last part of a file
SYNOPSIS
tail [ +-number[lbc][rf] ] [ file ]
tail [ -fr ] [ -n nlines ] [ -c ncharacters ] [ file ]
DESCRIPTION
Tail copies the named file to the standard output beginning at a designated place. If no file is named, the standard input is copied.
Copying begins at position +number measured from the beginning, or -number from the end of the input. Number is counted in lines, 1K
blocks or characters, according to the appended flag or Default is -10l (ten ell).
The further flag causes tail to print lines from the end of the file in reverse order; (follow) causes tail, after printing to the end, to
keep watch and print further data as it appears.
The second syntax is that promulgated by POSIX, where the numbers rather than the options are signed.
EXAMPLES
tail file
Print the last 10 lines of a file.
tail +0f file
Print a file, and continue to watch data accumulate as it grows.
sed 10q file
Print the first 10 lines of a file.
SOURCE
/sys/src/cmd/tail.c
BUGS
Tails relative to the end of the file are treasured up in a buffer, and thus are limited in length.
According to custom, option +number counts lines from 1, and counts blocks and characters from 0.
TAIL(1)