I came across the following problem, where file contents are overwritten using redirection. Can somebody please explain what cat << BAR seems to be doing and say why this is a problem? Explain the contents and relation between the two filenames used before the cat command. thanks
/tmp# echo... (2 Replies)
Hi,
in my script I need to execute the following command:
query $id 456 432
but it waits for a RETURN character from keyboard and therefore, it fails. I tried something like:
query $id 456 432 << '\n'
but, i'ts clear it is not correct. Is there any way to do this?
Thxs. (0 Replies)
Hi all,
I am working with the Grinder tool (unrelated to my question) to redirect the output of a program to a file as follows:
java -cp $CLASSPATH net.grinder.TCPProxy > grinder.txt
This is a proxy server which pipes output to a file. When I do something on my proxy, more and more goes to... (1 Reply)
Hi all,
Maybe someone is able to help:
Need to redirect the output of a command in realtime to a second command. Command-A executes a remote shell to another host, and outputs its results. Command-B displays a "dialog" with the outputs of Command-A.
Command-A Output:
Updating FileA... (2 Replies)
I just wondered if I'm understanding this command line correctly
cat 2>save1 0<memo | sort 2>save2 1>letter
This means that stdin will read from memo and if there is an error then stderr will write to save1. Am I correct in saying that the sort command will sort the memo file and write... (2 Replies)
for shell operators like <, >, <<, and >> do the LHS always have to be a process or device and the RHS a file or device?
Is it possible for the RHS to be a process? (1 Reply)
I want to redirect stderr and have the following peice of code
$ cat t1.ksh
#!/bin/ksh
func2()
{
diff /tmp/jdlkwjdlkejew /tmp/djlkwejdlewdjew >$OUTPUT_FILE 2>>$ERR_FILE
}
func1()
{
let counter=0
while
do
print -u2 "Error: In main function"
func2
let... (1 Reply)
So I have a existing file that I used the uniq command on and I need to save the output to the same file without changing the file name.
I have tried $ uniq filename > filename
then when I cat the file it then becomes blank like there is nothing inside.
any help would be much appreciated... (0 Replies)
OS : AIX 6.1
Shell : Korn
in the url
https://forums.oracle.com/forums/thread.jspa?threadID=361463&tstart=0
I came across a crontab entry example
00 23 * * 1,3,5 <complete shell script path> 1> <log file> 2>&1
From googling , I gathered that
0 - stdin
1 - stdout
2 - stderr
I... (5 Replies)
Hi,
Can I get some explanation around this bash redirection?
From what I have read, x < y means call the shell to redirect the output of y into x.
Does this mean that this sequence of commands is executed from right to left?
diff <(sort testfile.txt) <(sort testfile2.txt)
Thanks,
edit... (2 Replies)
Discussion started by: sand1234
2 Replies
LEARN ABOUT LINUX
debconf-set-selections
DEBCONF-SET-SELECTIONS(1) Debconf DEBCONF-SET-SELECTIONS(1)NAME
debconf-set-selections - insert new default values into the debconf database
SYNOPSIS
debconf-set-selections file
debconf-get-selections | ssh newhost debconf-set-selections
DESCRIPTION
debconf-set-selections can be used to pre-seed the debconf database with answers, or to change answers in the database. Each question will
be marked as seen to prevent debconf from asking the question interactively.
Reads from a file if a filename is given, otherwise from stdin.
WARNING
Only use this command to seed debconf values for packages that will be or are installed. Otherwise you can end up with values in the
database for uninstalled packages that will not go away, or with worse problems involving shared values. It is recommended that this only
be used to seed the database if the originating machine has an identical install.
DATA FORMAT
The data is a series of lines. Lines beginning with a # character are comments. Blank lines are ignored. All other lines set the value of
one question, and should contain four values, each separated by one character of whitespace. The first value is the name of the package
that owns the question. The second is the name of the question, the third value is the type of this question, and the fourth value (through
the end of the line) is the value to use for the answer of the question.
Alternatively, the third value can be "seen"; then the preseed line only controls whether the question is marked as seen in debconf's
database. Note that preseeding a question's value defaults to marking that question as seen, so to override the default value without
marking a question seen, you need two lines.
Lines can be continued to the next line by ending them with a "" character.
EXAMPLES
# Force debconf priority to critical.
debconf debconf/priority select critical
# Override default frontend to readline, but allow user to select.
debconf debconf/frontend select readline
debconf debconf/frontend seen false
OPTIONS --verbose, -v
verbose output
--checkonly, -c
only check the input file format, do not save changes to database
SEE ALSO debconf-get-selections(1) (available in the debconf-utils package)
AUTHOR
Petter Reinholdtsen <pere@hungry.com>
2011-06-22 DEBCONF-SET-SELECTIONS(1)