I tried this very code and I am still getting the undesired behavior from my original post. It's funny how the amount of bytes I get from FIFO seems to be system-dependent; more specifically, it seems hardware-dependent. When I tried the code in a very fast mac, with bash, cat-ing FIFO dumped the whole string 'Hello, world!' to stdout. On my (slower) yeeloong notebook, cat-ing FIFO only dumps the first few bytes of the string, and then a few more bytes, etc. Maybe the software in a macbook is designed differently, although the shell is the same (bash), I don't know. I have no clue as to why this happens. This is just so strange.
I posted a question on date intervals about a month back asking about how I could be able to go about a user entering the starting year/month/day and an ending year/month/day and then the script automatically cycling through each day of each month of each year that the user has specified.
I... (7 Replies)
In my server migration requirement, I need to compare if one file on old server is exactly the same as the corresponding file on the new server.
For diff and comm, the inputs need to be sorted. But I do not want to disturb the content of the file and need to find byte-to-byte match.
Please... (4 Replies)
Hi All
Can anyone please suggest me how to remove the last byte from a falt file .This is from the last line's last BYTE.
Please suggest me something.
Thank's and regards
Vinay (1 Reply)
divide input values into specified number (-100 or -200) according to the key (a1 or a2 ....)
For ex: if we give -100 in the command line it would create 100 number intervals (1-100, 100-200, 200-300) untill it covers the value 300 in a1.
Note: It should work the same even with huge numbers... (3 Replies)
Hi
I am new to expect. Please if any one can help on my issue its really appreciable. here is my issue:
I want expect script for random passwords and random commands generation.
please can anyone help me?
Many Thanks in advance (0 Replies)
Need to use dd to generate a large file from a sample file of random data. This is because I don't have /dev/urandom.
I create a named pipe then:
dd if=mynamed.fifo do=myfile.fifo bs=1024 count=1024
but when I cat a file to the fifo that's 1024 random bytes:
cat randomfile.txt >... (7 Replies)
There was an upload recently on generating a pseudo-random file when /dev/random does NOT exist.
This does not need /dev/random, /dev/urandom or $RANDOM either...
(I assume $RANDOM relies on the /dev/random device in some way.)
This code uses hexdump just because I like hexdump for ease of... (2 Replies)
Hi all,
I hope you can help me with the following question:
I have multiple tables like this:
Chr Start End Zygosity Gene
chr1 153233510 153233510 het LOR
chr1 153233615 153233615 hom LOR
chr1 153233701 153233701 hom LOR
chr1 ... (5 Replies)
Hello
I created 3 files by:
dd if=/dev/urandom bs=1024 count=1000000 of=./testfile1
dd if=/dev/urandom bs=1024 count=5000000 of=./testfile2
dd if=/dev/urandom bs=1024 count=10000000 of=./testfile3
Now I want to know how to make a change in a specific byte and/or line of theses files? (2 Replies)
hi all,
I wish to calculate the length between intervals whose are defined by a starting and an end possition. The data looks like this:
1 10
23 30
45 60
70 100...
The desired output should be:
13 # (23-10)
15 # (45-30)
10 # (70-60)...
I donīt know how to operate with different... (2 Replies)
Discussion started by: lsantome
2 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