Sponsored Content
Top Forums Programming How does commnad tail implement Post 26753 by killerserv on Friday 23rd of August 2002 01:13:41 AM
Old 08-23-2002
Captured from Man Page:


tail accepts two option formats: the new one, in which
numbers are arguments to the option letters, and the old
one, in which a `+' or `-' and optional number precede any
option letters.

If a number (`N') starts with a `+', tail begins printing
with the Nth item from the start of each file, instead of
from the end.

for more info you can check your man page. Might be diffrent from mine.
 

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

Commnad for getting bandwidth usage

Hi all Wanted to know if there is a command that gives me the bandwidth used at any point of time (in mbps). I pay for the bandwidth I have used and need to be alerted everytime I corss over a certain limit. Regards KS (5 Replies)
Discussion started by: skotapal
5 Replies

2. Shell Programming and Scripting

grep commnad

echo "Enter a,: \c" read answer echo case "$answer" in a|A) echo "Enter a file :\c" read $answer echo " Enter a string to be searched :\c" read $answer2 if then echo " file doesn't exist" ... (5 Replies)
Discussion started by: props
5 Replies

3. Shell Programming and Scripting

sorting file and unique commnad..

hello everyone.. I was wondering is there a effective way to sort file that contains colomns and numeric one. file 218900012192 8938929 8B8DF3664 1E7E2D59D5 0000 26538 1234 74024415 218900012979 8938929 8B8DF3664 1E7E2D59D5 0000 26538 1234 74024415 218900012992 8938929 8B8DF3664... (2 Replies)
Discussion started by: amon
2 Replies

4. UNIX for Dummies Questions & Answers

How to apply the awk commnad ?

Hi, I have a file and the contents of the file is say World World World Now i need to append some more words in each of the line and the the output of the file should like the one below Will India win the World Cup? Will India win the World Cup? Will India win the... (3 Replies)
Discussion started by: preethgideon
3 Replies

5. UNIX for Dummies Questions & Answers

how to use find commnad to show only path of the result

Hello all say i like to find files i do : find . -name "*.txt" but if i like to find ( and print out ) only the path's where the files are ( the *.txt files ) what can i add to the find command ? (1 Reply)
Discussion started by: umen
1 Replies

6. UNIX for Dummies Questions & Answers

User History and commnad log

Dear All I had a UNIX ( Sun solaris ) os. There are many user on that server. Now i want to find during last week who had log in to the sever and which commnad are executed by them? I also want to from which IP they had log in to the server. Is there any log file generated for user in... (5 Replies)
Discussion started by: jaydeep_sadaria
5 Replies

7. Shell Programming and Scripting

how to implement this

Hi all, could any of you please help me on my problem.. we are doing FTP (one report out put) from one server to another server through unix shell script program. Due to the network issues, some times FTP process is hanging. So we planned to modify the existing program with the following... (2 Replies)
Discussion started by: kishore_jasthi
2 Replies

8. Shell Programming and Scripting

how can we perform calculation on the ouput of the commnad

Hello I am very new to unix scripting. The below is the ouput of my one command, now i want to use the two below values 611 and 572 from the output of the command . in the ouput i want 39 which would be come by subtracting 572 to 611. please suggest how can we perform subtraction of... (6 Replies)
Discussion started by: singhald
6 Replies

9. UNIX for Advanced & Expert Users

zsh and watch commnad

Hi Guys i have set the watch command on my shell watch=all but this will report when i open and close a shell, is there a way so that it will ignore me user but only when i am on my machine i can set it to watch=notme but that will not detect if someone su -<my... (0 Replies)
Discussion started by: ab52
0 Replies

10. Shell Programming and Scripting

Joining multiple files tail on tail

I have 250 files that have 16 columns each - all numbered as follows stat.1000, stat.1001, stat.1002, stat.1003....stat.1250. I would like to join all 250 of them together tail by tail as follows. For example stat.1000 a b c d e f stat.1001 g h i j k l So that my output... (2 Replies)
Discussion started by: kayak
2 Replies
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
All times are GMT -4. The time now is 02:25 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy