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.
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 FREEBSD
tail
TAIL(1) BSD General Commands Manual TAIL(1)NAME
tail -- display the last part of a file
SYNOPSIS
tail [-F | -f | -r] [-q] [-b number | -c number | -n number] [file ...]
DESCRIPTION
The tail utility displays the contents of file or, by default, its standard input, to the standard output.
The display begins at a byte, line or 512-byte block location in the input. Numbers having a leading plus ('+') sign are relative to the
beginning of the input, for example, ``-c +2'' starts the display at the second byte of the input. Numbers having a leading minus ('-') sign
or no explicit sign are relative to the end of the input, for example, ``-n 2'' displays the last two lines of the input. The default start-
ing location is ``-n 10'', or the last 10 lines of the input.
The options are as follows:
-b number
The location is number 512-byte blocks.
-c number
The location is number bytes.
-f The -f option causes tail to not stop when end of file is reached, but rather to wait for additional data to be appended to the
input. The -f option is ignored if the standard input is a pipe, but not if it is a FIFO.
-F The -F option implies the -f option, but tail will also check to see if the file being followed has been renamed or rotated. The
file is closed and reopened when tail detects that the filename being read from has a new inode number.
If the file being followed does not (yet) exist or if it is removed, tail will keep looking and will display the file from the begin-
ning if and when it is created.
The -F option is the same as the -f option if reading from standard input rather than a file.
-n number
The location is number lines.
-q Suppresses printing of headers when multiple files are being examined.
-r The -r option causes the input to be displayed in reverse order, by line. Additionally, this option changes the meaning of the -b,
-c and -n options. When the -r option is specified, these options specify the number of bytes, lines or 512-byte blocks to display,
instead of the bytes, lines or blocks from the beginning or end of the input from which to begin the display. The default for the -r
option is to display all of the input.
If more than a single file is specified, each file is preceded by a header consisting of the string ``==> XXX <=='' where XXX is the name of
the file unless -q flag is specified.
EXIT STATUS
The tail utility exits 0 on success, and >0 if an error occurs.
EXAMPLES
To display the last 500 lines of the file foo:
$ tail -n 500 foo
Keep /var/log/messages open, displaying to the standard output anything appended to the file:
$ tail -f /var/log/messages
SEE ALSO cat(1), head(1), sed(1)STANDARDS
The tail utility is expected to be a superset of the IEEE Std 1003.2-1992 (``POSIX.2'') specification. In particular, the -F, -b and -r
options are extensions to that standard.
The historic command line syntax of tail is supported by this implementation. The only difference between this implementation and historic
versions of tail, once the command line syntax translation has been done, is that the -b, -c and -n options modify the -r option, i.e., ``-r
-c 4'' displays the last 4 characters of the last line of the input, while the historic tail (using the historic syntax ``-4cr'') would
ignore the -c option and display the last 4 lines of the input.
HISTORY
A tail command appeared in PWB UNIX.
BSD March 16, 2013 BSD