Modern shells can hold data in memory by using variables. Here's an example:
producing:
So this holds the last 3 lines of Lincoln's Gettysburg address in memory, variable v1 , then removes the file, and finally writes the saved data to the file. One could also just truncate the file if one wanted to keep the inode.
This obviously has risks -- if the code is wrong or if something else bad happens, it's possible that the entire file could be lost. Of course, one has backups for such occasions.
This method works in the versions of Linux and bash as noted. Will it work in your system? I don't know, but you could test it, and, as usual, be prepared with a backup if things go awry.
Hi,
There seems to some hack attempts in my site. I have attached the index page of my site and I need to remove the below lines from the index page. The below lines are at the center of the file.
-->
</style>
<script>E V A L( unescape(... (5 Replies)
All,
I have a text file with several entries like below:
personname
personname.domain.com
I know there is a way to use vi to remove only the personname.domain.com line. Can someone help? I believe that it involves /s/g/ something...I just can't remember the exact syntax.
Thanks (2 Replies)
Hi gurus,
i'm trying to remove a number of lines from a large file using the following command:
sed '1,5000d' oldfile > newfile
Somehow the lines in the old file are not deleted...
Am I doing this wrongly? Any suggestions? :confused:
Thanks! :)
wee (10 Replies)
A small question
I have a test.txt file
I have contents as:
a:google
b:yahoo
:
c:facebook
:
d:hotmail
How do I remove the line with :
my output should be
a:google
b:yahoo
c:facebook
d:hotmail (5 Replies)
Hi,
I'm not a expert in shell programming, so i've come here to take help from u gurus.
I'm trying to tailor a csv file that i got to make it work for the LOAD FROM command.
I've a datatable csv of the below format -
--in file format
xx,xx,xx ,xx , , , , ,,xx,
xxxx,, ,, xxx,... (11 Replies)
Hey Gang-
I have a list of servers. I want to exclude servers that begin with and end with certain characters. Is there an easy command to do this?
Example
wvm1234dev
wvm1234pro
uvm1122dev
uvm1122bku
uvm1344dev
I want to exclude any lines that start with "wvm" OR "uvm" AND end... (7 Replies)
I have two files, a keepout.txt and a database.csv. They're unsorted, but could be sorted.
keepout:
user1
buser3
anuser19
notheruser27
database:
user1,2343,"information about",field,blah,34
user2,4231,"mo info",etc,stuff,43
notheruser27,4344,"hiya",thing,more thing,423... (4 Replies)
Hello everyone,
Although it seems easy, I've been stuck with this problem for a moment now and I can't figure out a way to get it done.
My problem is the following:
I have a file where each line is a sequence of IP addresses, example :
10.0.0.1 10.0.0.2
10.0.0.5 10.0.0.1 10.0.0.2... (5 Replies)
I have been searching and trying to come up with an awk that will perform the following on a
converted text file (original is a pdf).
1. Since the first two lines are (begin with) text they are removed
2. if $1 is a number then all text is merged (combined) into one line until the next... (3 Replies)
Discussion started by: cmccabe
3 Replies
LEARN ABOUT OPENSOLARIS
tail
tail(1) User Commands tail(1)NAME
tail - deliver the last part of a file
SYNOPSIS
/usr/bin/tail [+-s number [lbcr]] [file]
/usr/bin/tail [-lbcr] [file]
/usr/bin/tail [+- number [lbcf]] [file]
/usr/bin/tail [-lbcf] [file]
/usr/xpg4/bin/tail [-f | -r] [-c number | -n number] [file]
/usr/xpg4/bin/tail [+- number [l | b | c] [f]] [file]
/usr/xpg4/bin/tail [+- number [l] [f | r]] [file]
DESCRIPTION
The tail utility copies the named file to the standard output beginning at a designated place. If no file is named, the standard input is
used.
Copying begins at a point in the file indicated by the -cnumber, -nnumber, or +-number options (if +number is specified, begins at distance
number from the beginning; if -number is specified, from the end of the input; if number is NULL, the value 10 is assumed). number is
counted in units of lines or byte according to the -c or -n options, or lines, blocks, or bytes, according to the appended option l, b,
or c. When no units are specified, counting is by lines.
OPTIONS
The following options are supported for both /usr/bin/tail and /usr/xpg4/bin/tail. The -r and -f options are mutually exclusive. If both
are specified on the command line, the -f option is ignored.
-b Units of blocks.
-c Units of bytes.
-f Follow. If the input-file is not a pipe, the program does not terminate after the line of the input-file has been copied, but enters
an endless loop, wherein it sleeps for a second and then attempts to read and copy further records from the input-file. Thus it can
be used to monitor the growth of a file that is being written by some other process.
-l Units of lines.
-r Reverse. Copies lines from the specified starting point in the file in reverse order. The default for r is to print the entire file
in reverse order.
/usr/xpg4/bin/tail
The following options are supported for /usr/xpg4/bin/tail only:
-c number The number option-argument must be a decimal integer whose sign affects the location in the file, measured in bytes, to begin
the copying:
+ Copying starts relative to the beginning of the file.
- Copying starts relative to the end of the file.
none Copying starts relative to the end of the file.
The origin for counting is 1; that is, -c+1 represents the first byte of the file, -c-1 the last.
-n number Equivalent to -cnumber, except the starting location in the file is measured in lines instead of bytes. The origin for count-
ing is 1. That is, -n+1 represents the first line of the file, -n-1 the last.
OPERANDS
The following operand is supported:
file A path name of an input file. If no file operands are specified, the standard input is used.
USAGE
See largefile(5) for the description of the behavior of tail when encountering files greater than or equal to 2 Gbyte ( 2^31 bytes).
EXAMPLES
Example 1 Using the tail Command
The following command prints the last ten lines of the file fred, followed by any lines that are appended to fred between the time tail is
initiated and killed.
example% tail -f fred
The next command prints the last 15 bytes of the file fred, followed by any lines that are appended to fred between the time tail is initi-
ated and killed:
example% tail -15cf fred
ENVIRONMENT VARIABLES
See environ(5) for descriptions of the following environment variables that affect the execution of tail: LANG, LC_ALL, LC_CTYPE, LC_MES-
SAGES, and NLSPATH.
EXIT STATUS
The following exit values are returned:
0 Successful completion.
>0 An error occurred.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
/usr/bin/tail
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWcsu |
+-----------------------------+-----------------------------+
|CSI |Enabled |
+-----------------------------+-----------------------------+
/usr/xpg4/bin/tail
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWxcu4 |
+-----------------------------+-----------------------------+
|CSI |Enabled |
+-----------------------------+-----------------------------+
|Interface Stability |Standard |
+-----------------------------+-----------------------------+
SEE ALSO cat(1), head(1), more(1), pg(1), dd(1M), attributes(5), environ(5), largefile(5), standards(5)NOTES
Piped tails relative to the end of the file are stored in a buffer, and thus are limited in length. Various kinds of anomalous behavior can
happen with character special files.
SunOS 5.11 13 Jul 2005 tail(1)