02-22-2018
Quote:
Originally Posted by
florachavezz
How about SED commands? Will they work for such a task? I should extract records based on a particular condition in my project.
Sorry, I don't quite understand the point here. In your posting, you wrote:
My only question is how do I add to my code so that when I try to divide by zero it will show Cannot divide by zero or invalid? I don't see how this relates to record extraction.
If you have questions about other subjects, please create separate posts.
10 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
Hey can anyone tell me the korn script code to implement an interactive integer calculator using the shell's built in arithemetic expression evaluation (2 Replies)
Discussion started by: sahithi_khushi
2 Replies
2. Shell Programming and Scripting
I am pretty new to the Unix word, and have created a working calculator script. I have one problem. It doesn't use any decimals, it rounds off to the nearest whole number.
1 #!/bin/ksh
2 while true; do
3 echo -n "Enter the first integer: "; read IN1
4 test... (2 Replies)
Discussion started by: ironhead3fan
2 Replies
3. UNIX for Dummies Questions & Answers
hi, im new to the unix system and scripting and was wondering if anyone could help me with this problem iv been havin... i want the system to:
1. ask me for a number
2. ask me for a command to use on that number (* + - /)
3. ask me for another number
4. then ask me for another command, if the... (2 Replies)
Discussion started by: jdougy
2 Replies
4. Shell Programming and Scripting
I have 2 questions.
1) Is there a means of directing output to a file (">") while making it still output to the console?
I have a script that calls another lengthy script.
2) I can direct the output of the lengthy script and grep it for the words "good" or "bad" to know if I need the run... (2 Replies)
Discussion started by: mrwatkin
2 Replies
5. Shell Programming and Scripting
Hi Guys,
I found this code in net.. it is working fine..
But can anybody explain me the sed statement used in the code..
echo "Enter the expression:\c"
read express
eval echo "$express"|sed 's/^/'$precision' \
/'|bc -l|\
sed -n '1,${
/syntax/!{
}
... (2 Replies)
Discussion started by: mac4rfree
2 Replies
6. Shell Programming and Scripting
hi,
I have some problems in my simple script about the redirect echo stdout command inside a condition. Why is the echo command inside the elif still execute in the else command
Here are my simple script
After check on the two diff output the echo stdout redirect is present in two diff... (3 Replies)
Discussion started by: jao_madn
3 Replies
7. Homework & Coursework Questions
Use and complete the template provided. The entire template must be completed. If you don't, your post may be deleted!
1. The problem statement, all variables and given/known/data:
Script a simple calculator. In the command line enter the script file
/home/etc/mycalc or /home/etc/mycalc 1 +... (6 Replies)
Discussion started by: herb bertz
6 Replies
8. Shell Programming and Scripting
HI
My doubt may be basic one but I need to get it clarified..
When i use "if" condition that checks for many AND, OR logical conditions
like
if ]; then
return 0
fi
Even the if condition fails it returns as zero.. Any clue..
But if i add else condition like
if ]; ... (2 Replies)
Discussion started by: Priya Amaresh
2 Replies
9. Shell Programming and Scripting
I wrote a code to find codons in a DNA string. The only problem I have is how do I make the code only work for a file with DNA. This means the file only has the characters a,c,g,t and no white space characters. (3 Replies)
Discussion started by: germany1517
3 Replies
10. UNIX for Beginners Questions & Answers
So have I got this :
#!/bin/bash
clear
echo "Enter the first number:"
read n1
echo "Choose an operation:"
echo "1. add"
echo "2. subtract"
echo "3. multiply"
echo "4. divide"
read opr
echo "Enter the second number:"
read n2 (1 Reply)
Discussion started by: mugiboya
1 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)