It is working fine, if I have only one space. But in my input file, I might have more than single space say " " or " " or " " etc. But I dont know the exact number of spaces.
Hello All,
I have a file of the format
****
123 abc ABC
456 bcd BCD
789 def
112 ghi GHI
223 jkl
344 mno MNO
****
I am trying to extract the lines that have no values in the third field (in this case, this would be
789 def
223 jkl
Can anyone please help??... (1 Reply)
I've got a very peculiar situation. I'm trying to find out if we can compare null fields with non-null. I've output csv files from SQL and Oracle. I need to compare each field from the files, and then find out any differences. The files usualy have over 500 fields, and send the resule to DBA.... (8 Replies)
void disptree(node *ptr)
{
if ((ptr->left) !=NULL)
disptree(ptr->left);
cout<<"Position:"<<ptr->pos<<" Data:"<<ptr->data<<endl;
if ((ptr->right)!=NULL;
disptree(ptr->right);
}
i'm getting a segmentation fault at the red line. i cannot understand what's the problem.... (3 Replies)
I have an input file having 7 fields delimited by ,
eg :
1,ABC,hg,1,2,34,3
2,hj,YU,2,3,4,
3,JU,kl,4,5,7,
4,JK,KJ,3,56,4,5
The seventh field here in some lines is empty, whereas the other lines there is a value.
How do I insert string NULL at this location (7th loc) for these lines where... (8 Replies)
How are these two different? They both prevent output and error from being displayed. I don't see the use of the "&"
echo "hello" > /dev/null 2>&1
echo "hello" > /dev/null 2>1 (3 Replies)
Hello All,
I have this question that how to check for an array for NULL?
For eg.
#include<iostream.h>
using namespace std;
int main()
{
char arr;
if(arr == NULL)
{
cout<<"NULL";
}
}
Thanks a lott in advance!!! (3 Replies)
Hi I need to check the output of a string to null. For eg the output I get for $KIT is empty. So want to echo something when the output is empty.
How can I do that?
Thanks in advance (6 Replies)
I apologize if this question has been answered else where or is too elementary.
I ran across a KSH script (long unimportant story) that does this:
if ; then
CAS_SRC_LOG="/var/log/cas_src.log 2>&1"
else
CAS_SRC_LOG="/dev/null 2>&1"
fithen does this:
/usr/bin/echo "heartbeat:... (5 Replies)
Hi, (i'm sorry for my english)
I'm a problem on boot sco unix 5.0.5 open server.
this stop at "Checking protected password and checking subsystem databases"
(See this image )
I'm try this:
1) http://www.digipedia.pl/usenet/thread/50/37093/#post37094
2) SCO: SCO Unix - Server hangs... (9 Replies)
i have this code
for i in `cat sql_output.txt`
do
-- some script commands
done
sql_output.txt has 1 column with employee_ids
If the sql_output.txt is null then the do loop should not execute.
How can i implement this.
for i in `cat sql_output.txt`
If i is null or empty
then ... (5 Replies)
Discussion started by: rafa_fed2
5 Replies
LEARN ABOUT DEBIAN
shell-quote
SHELL-QUOTE(1p) User Contributed Perl Documentation SHELL-QUOTE(1p)NAME
shell-quote - quote arguments for safe use, unmodified in a shell command
SYNOPSIS
shell-quote [switch]... arg...
DESCRIPTION
shell-quote lets you pass arbitrary strings through the shell so that they won't be changed by the shell. This lets you process commands
or files with embedded white space or shell globbing characters safely. Here are a few examples.
EXAMPLES
ssh preserving args
When running a remote command with ssh, ssh doesn't preserve the separate arguments it receives. It just joins them with spaces and
passes them to "$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 v5.8.4 2005-05-03 SHELL-QUOTE(1p)