06-18-2001
It's good to pick up these sorts of shortcuts to save a lot of time when in a hurry or under pressure - the little things like knowing a flag here and there often make the difference between finding a vital piece of information that can lead to solving a problem.
As with most general issues there are many ways to do things in UNIX - you could have piped tail into the more command to achieve the same effect, variety is the spice of of life!
10 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
Hi, just a quick question really on what the <<! at the end of a line actually means ? as you can see i have an oracle startup script that has an sqlplus command. im making a guess here, so correct me if im wrong but the "startup" and "exit" commands that follow are sqlplus command and not unix... (3 Replies)
Discussion started by: hcclnoodles
3 Replies
2. UNIX for Dummies Questions & Answers
how can I add data from command line to end of file? (3 Replies)
Discussion started by: bryan
3 Replies
3. Shell Programming and Scripting
hi,
could anyone tell me the command to append spaces at the end of the line.
for example, i need 1000 spaces after the word "helloworld"
echo "helloworld " i need to achieve this in someother way hardcoding 1000 spaces is not practical.
as i am totally new... (3 Replies)
Discussion started by: kavithacs
3 Replies
4. Programming
hello,
i use this command in my code:
(void) sprintf ( LBuf, "/bin/sed 's/\\//g' %s > %s", tmp1,tmp2);
but i get this error :
sh: syntax error at line 1:'end of file' unexpected
any help please
thank you (1 Reply)
Discussion started by: kamel.seg
1 Replies
5. Shell Programming and Scripting
Hi,
I want to add \n as a EOF at the end of file if it does't exist in a single command. How to do this?
when I use command
echo "1\n" > a.txt
and
od -c a.txt
0000000 1 \n \n
0000003
How does it differentiate \n and eof in this case?
Regards,
Venkat (1 Reply)
Discussion started by: svenkatareddy
1 Replies
6. Shell Programming and Scripting
I am looking to change a data file into a javascript string and this is the code that I am using:
sed -i '' -e 's/^/str += "/' -e 's/$/";/' file.xml
The first part
-e 's/^/str += "/'
works as intended, but the second part
-e 's/$/";/'
adds an additional newline to my file, so that instead of... (3 Replies)
Discussion started by: figaro
3 Replies
7. UNIX for Dummies Questions & Answers
I have text file which is a tab delimited one. Sample data from the file is shown below:
unix is\ great\ os
linux\ is superb
I want to replace that backslash with empty string preserving the tab delimiter. Output should be
unix is great os
linux is ... (3 Replies)
Discussion started by: p.akhilreddy4u
3 Replies
8. Shell Programming and Scripting
Hi ,
Am trying to send mail using the mail command, but the mail command is working but its not sending automatically after pressing .(dot) in the command prompt it sends . How to achieve that. Also it showing the below line after pressing the dot .
/home/abc1/dead.letter... Saved message in... (5 Replies)
Discussion started by: rogerben
5 Replies
9. Shell Programming and Scripting
Oracle Enterprise Linux
We want to track how long a process takes to complete its execution. This is what we want in the schell script
Before the process is started , get the time with date, hours and minutes
execute the process
After the process has ended , get the time with date,... (5 Replies)
Discussion started by: omega3
5 Replies
10. Shell Programming and Scripting
hello Team,
I am looking for sed command or script which will append word at end of line. for example. I want to validate particular filesystem with mount |<filesystem name> command. if nodev parameter is not there then it should add in the fstab file with receptive to the filesystem.
# mount... (8 Replies)
Discussion started by: ghpradeep
8 Replies
LEARN ABOUT OPENDARWIN
tail
TAIL(1) BSD General Commands Manual TAIL(1)
NAME
tail -- display the last part of a file
SYNOPSIS
tail [-F | -f | -r] [-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
starting 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. The -F option is ignored if
reading from standard input rather than a file.
-n number
The location is number lines.
-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.
DIAGNOSTICS
The tail utility exits 0 on success, and >0 if an error occurs.
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
June 6, 1993 BSD