Hello all. Is there a way to redirect output to more than one file at a time?
I have a method1() that writes to a logfile. In the method cksums are done on files by doing a
"for i in `ls`; do
cksum $i > $LOGFILE
done
"
In the logfile I want to show the cksums under each directory like... (2 Replies)
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)
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)
Hi gurus,
I have a question, need some of your inputs...
I have a command like this :
export LINE_COUNT=`wc -l test.dat | awk '{print $1}'`
echo $LINE_COUNT --- > gives me 2 which is fine as the file has 2 lines.
This works fine if the file test.dat is present but in case... (3 Replies)
Hi,
when I try to redirect input and the command is described as a string within an array redirection does not work. why?
#!/bin/bash
dir=("tail < ./hello.txt")
tail < ./hello.txt #works
${dir} #does not work (2 Replies)
Hi,
Can I get some explanation around this bash redirection?
From what I have read, x < y means call the shell to redirect the output of y into x.
Does this mean that this sequence of commands is executed from right to left?
diff <(sort testfile.txt) <(sort testfile2.txt)
Thanks,
edit... (2 Replies)
Discussion started by: sand1234
2 Replies
LEARN ABOUT CENTOS
shell-quote
SHELL-QUOTE(1) User Contributed Perl Documentation SHELL-QUOTE(1)NAME
shell-quote - quote arguments for safe use, unmodified in a shell command
SYNOPSIS
shell-quote [switch]... arg...
DESCRIPTION
shell-quote lets you pass arbitrary strings through the shell so that they won't be changed by the shell. This lets you process commands
or files with embedded white space or shell globbing characters safely. Here are a few examples.
EXAMPLES
ssh preserving args
When running a remote command with ssh, ssh doesn't preserve the separate arguments it receives. It just joins them with spaces and
passes them to "$SHELL -c". This doesn't work as intended:
ssh host touch 'hi there' # fails
It creates 2 files, hi and there. Instead, do this:
cmd=`shell-quote touch 'hi there'`
ssh host "$cmd"
This gives you just 1 file, hi there.
process find output
It's not ordinarily possible to process an arbitrary list of files output by find with a shell script. Anything you put in $IFS to
split up the output could legitimately be in a file's name. Here's how you can do it using shell-quote:
eval set -- `find -type f -print0 | xargs -0 shell-quote --`
debug shell scripts
shell-quote is better than echo for debugging shell scripts.
debug() {
[ -z "$debug" ] || shell-quote "debug:" "$@"
}
With echo you can't tell the difference between "debug 'foo bar'" and "debug foo bar", but with shell-quote you can.
save a command for later
shell-quote can be used to build up a shell command to run later. Say you want the user to be able to give you switches for a command
you're going to run. If you don't want the switches to be re-evaluated by the shell (which is usually a good idea, else there are
things the user can't pass through), you can do something like this:
user_switches=
while [ $# != 0 ]
do
case x$1 in
x--pass-through)
[ $# -gt 1 ] || die "need an argument for $1"
user_switches="$user_switches "`shell-quote -- "$2"`
shift;;
# process other switches
esac
shift
done
# later
eval "shell-quote some-command $user_switches my args"
OPTIONS --debug
Turn debugging on.
--help
Show the usage message and die.
--version
Show the version number and exit.
AVAILABILITY
The code is licensed under the GNU GPL. Check http://www.argon.org/~roderick/ or CPAN for updated versions.
AUTHOR
Roderick Schertler <roderick@argon.org>
perl v5.16.3 2010-06-11 SHELL-QUOTE(1)