The file still exists until everything with it open, closes it or quits.
Try truncating it, i.e. overwriting it with nothing, instead of deleting it. Having it open can't prevent that from happening, and tail -f is usually smart enough to seek back to the beginning.
In bash, I need to send the STDOUT and STDERR from a command to one file, and then just STDERR to another file. Doing one or the other using redirects is easy, but trying to do both at once is a bit tricky. Anyone have any ideas? (9 Replies)
Is there a way to redirect all stdout to a file implicitly - like defining stdout=/home/me/process.log - so that all "echo" commands in several scripts/subscripts are written to that file; instead of having to edit all scripts to redirect the "echo" (e.g. echo 'This is a test ' >>... (1 Reply)
Hi,
I am trying to execute a command like this:
find ./ -name "*.gz" -exec sh -c 'zcat {} | awk -f parse.awk' \; >> output
If I want to print the filename, i generally use the -print argument to the find command but when I am redirecting the output to a file, how can I print just the... (2 Replies)
I have an executable that, depending on its input, outputs to either one file or several. It usually prints nothing on screen. The usual way to call this program is to specify an input and output filenames, like this:
./executable.exe -i inputfile -o outputfileIt will then try to use the output... (1 Reply)
can anyone help me in making singleline command for
Capital Letters are folders ,small letter are files
X,Y,Z are subfolders of A
as shown below
A - X,Y,Z
Folder X has three files a.txt,b.txt,c.txt similarly Y,Z.
as shown below
X- a.txt,b.txt,c.txt
Y- a.txt,b.txt,c.txt
Z-... (4 Replies)
Hi everybody,
I am trying to do the thing you see in the title, and I can't simply do
a=$(svn up)
echo $a
because the program (svn) gives output on lots of lines and in the variable the output is stored on only one line (resulting in a horribly formatted text). Any tips?
Thanks,... (2 Replies)
Hello,
I have a script (videostream.sh) which invokes the GStreamer command-line tool gst-launch with all the correct command line parameters. When I invoke this program, I add the '&' character at the end to make it a background task, so that my script can complete and exit, i.e.
gst-launch... (1 Reply)
I have a C program that continously outputs info to stdout. The problem is that I am redirecting the stdout and stderr to a file and stdout is written at the end of the problem rather than continously to the file. This could be a problem if for example the program is killed and the stdout output is... (3 Replies)
Hello,
I'm strugling with some redirecting and all help is apreciated.
The following program is working as expected, but the result of the AT command doesn't go to any file.
Thanks in advance for the help.
#!/bin/bash
modem=/dev/ttyUSB1
file=/root/imsi.txt
# print error to stderr and exit... (4 Replies)
hi,
OK. I am writing a bash script, and it is almost working for me.
Problem 1: I currently have stout sent to a file (stout.miRNA.bash.$date_formatted) which I would like to have work inside my loop, but when I move it, it just prints to the screen.
Problem 2: I have a second file... (18 Replies)
Discussion started by: hmortens
18 Replies
LEARN ABOUT PHP
seek
seek(n) Tcl Built-In Commands seek(n)
__________________________________________________________________________________________________________________________________________________NAME
seek - Change the access position for an open channel
SYNOPSIS
seek channelId offset ?origin?
_________________________________________________________________DESCRIPTION
Changes the current access position for channelId.
ChannelId must be an identifier for an open channel such as a Tcl standard channel (stdin, stdout, or stderr), the return value from an
invocation of open or socket, or the result of a channel creation command provided by a Tcl extension.
The offset and origin arguments specify the position at which the next read or write will occur for channelId. Offset must be an integer
(which may be negative) and origin must be one of the following:
start The new access position will be offset bytes from the start of the underlying file or device.
current The new access position will be offset bytes from the current access position; a negative offset moves the access position back-
wards in the underlying file or device.
end The new access position will be offset bytes from the end of the file or device. A negative offset places the access position
before the end of file, and a positive offset places the access position after the end of file.
The origin argument defaults to start.
The command flushes all buffered output for the channel before the command returns, even if the channel is in nonblocking mode. It also
discards any buffered and unread input. This command returns an empty string. An error occurs if this command is applied to channels
whose underlying file or device does not support seeking.
Note that offset values are byte offsets, not character offsets. Both seek and tell operate in terms of bytes, not characters, unlike
read.
EXAMPLES
Read a file twice:
set f [open file.txt]
set data1 [read $f]
seek $f 0
set data2 [read $f]
close $f
# $data1 == $data2 if the file wasn't updated
Read the last 10 bytes from a file:
set f [open file.data]
# This is guaranteed to work with binary data but
# may fail with other encodings...
fconfigure $f -translation binary
seek $f -10 end
set data [read $f 10]
close $f
SEE ALSO
file(n), open(n), close(n), gets(n), tell(n), Tcl_StandardChannels(3)KEYWORDS
access position, file, seek
Tcl 8.1 seek(n)