Login or Register to Ask a Question and Join Our Community


Shell Programming and Scripting

Change existing variable value only user enters non-empty string.

Login to Discuss or Reply to this Discussion in Our Community

 
Thread Tools Search this Thread
Top Forums Shell Programming and Scripting Change existing variable value only user enters non-empty string.
# 8  
Old 05-20-2010
Kchinnam, you are seeing the newlines ('\n") in your od output because you are using the echo command to pipe the variable in question to od. The echo command adds a newline to its output by design.

Try the following example
Code:
uid="scott"
echo "${uid}" |  od -bcx
printf "${uid}" |  od -bcx

gid=
echo "${gid}" |  od -bcx
printf "${gid}" |  od -bcx

Here is the output from this example
Code:
$ ./example
0000000  163 143 157 164 164 012
           s   c   o   t   t  \n
            6373    746f    0a74
0000006
0000000  163 143 157 164 164
           s   c   o   t   t
            6373    746f    0074
0000005
0000000  012
          \n
            000a
0000001
$
Login or Register to Ask a Question

Previous Thread | Next Thread

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Change date time stamp of existing file

I have a file hello.txt which was created today (today's date timestamp) I wish to change its date timestamp (access, modified, created) to 1 week old i.e one week from now. uname -a SunOS mymac 5.11 11.2 sun4v sparc sun4v Can you please suggest a easy way to do that ? (12 Replies)
Discussion started by: mohtashims
12 Replies

2. Shell Programming and Scripting

Script stops running after assigning empty string for a variable

Hi, This is the first time I see something like this, and I don't why it happens. Please give me some help. I am really appreciate it. Basically I am trying to remove all empty lines of an input.. #!/bin/bash set -e set -x str1=`echo -e "\nhaha" | grep -v ^$` #str2=`echo -e "\n" |... (4 Replies)
Discussion started by: yoyomano
4 Replies

3. Shell Programming and Scripting

How do I change a variable to something only if it's empty?

I feel like it is just a matter of using the $ operators correctly, but I can't seem to get it... hostname="network" ip="192.168.1.1" netmask="" variables=( $hostname $ip $netmask ) for var in ${variables} do if ; then $var="--" fi done echo... (7 Replies)
Discussion started by: etranman1
7 Replies

4. Shell Programming and Scripting

How to change last character in string with a variable value.

Hey Guys, I have text such as this. 28003,ALCORN,2 28009,BENTON,2 28013,CALHOUN,2 28017,CHICKASAW,2 47017,CARROLL,2 05021,CLAY,0 The last digit after the final "," is a variable value. This is the base file. I have to do further execution on this file later and I need to update the... (7 Replies)
Discussion started by: chagan02
7 Replies

5. Shell Programming and Scripting

awk: change string variable

Hi. How to change string variable in awk? for example, I parse with awk script text file named some_name_with_extension.txt I want to print only some_name in my script .... varCompName = FILENAME print varCompName How to put not all symbols from FILENAME to variable? thank you This... (4 Replies)
Discussion started by: cintlt
4 Replies

6. Shell Programming and Scripting

BASH - set specific user variable via string operators

Apologies for the utter triviality of this question, but we all have to start somewhere! I've also tried searching but this question is pretty vague so I didn't (a) really know what to search for or (b) get many relevant hits to what I did search for. Anyway, I'm in the process of self-teaching... (1 Reply)
Discussion started by: u5j84
1 Replies

7. Solaris

Add existing user into an existing group

Pre: no gpasswd/adduser there is just usermod can be used, also there is no -a option for usermod. How should I add a user into a group? (4 Replies)
Discussion started by: a2156z
4 Replies

8. UNIX for Dummies Questions & Answers

New Variable with Existing variable( Urgent)

hi all, i want use the variable value as a new variable name. print output of new variable. for i in COMPUTER1 COMPUTER2 do flag_name=${i}_FLAG eval ${flag_name}=123 echo $i'_FLAG' done output is COMPUTER1_FLAG COMPUTER2_FLAG i need output as 123 123 (2 Replies)
Discussion started by: arvindng
2 Replies

9. UNIX for Dummies Questions & Answers

how can i change the date of an existing file

Hi, Plz suggest me how can i change the date of a file. Suppose my file has been created in some date and i want to give it present date. How can i do this???? (2 Replies)
Discussion started by: adityam
2 Replies

10. Shell Programming and Scripting

if test for empty and non-existing file

How to write this condition in ksh? if myfile is empty or myfile does not exist then do action1 fi is this OK? if ] -o ] then then do action1 fi Thanks. (3 Replies)
Discussion started by: GNMIKE
3 Replies
Login or Register to Ask a Question

LEARN ABOUT HPUX

secure_sid_scripts

secure_sid_scripts(5)						File Formats Manual					     secure_sid_scripts(5)

NAME

       secure_sid_scripts - controls whether setuid and setgid bits on scripts are honored

VALUES

   Failsafe
   Default
   Allowed values
   Recommended values
DESCRIPTION

       This  tunable  controls	whether and bits on executable scripts have any effect.  Honoring on scripts make a system vulnerable to attack by
       malicious users.

       The default value for this variable is 1, indicating that bits are to be ignored by the execve(2) system call  for  higher  security.   The
       tunable	can  be set to 0 for a compatibility with older releases at the expense of security.  Hewlett-Packard strongly recommends that you
       not change the value of this tunable unless there is an urgent need to do so.

       When a script with bits is executed, the kernel generates the following error message to both the terminal controlling and the system  log.
       (To view the error message, use dmesg(1M) or inspect

   Who is Expected to Change This Tunable?
       Administrator.

   Restrictions on Changing
       Changes to this tunable take effect for new scripts started after the change.

   When Should the Value of This Tunable Be Changed?
       This  tunable  controls	operational  modes  rather  than data structure sizes and limits.  The appropriate setting for a system depends on
       whether you consider security or compatibility to be most important.

       A value of is compatible with previous releases of HP-UX, but it is also less secure.

       A value of provides security against race condition attacks exploiting scripts.

   What Are the Side Effects of Changing the Value
       This tunable controls only executable scripts (not programs) with bit set.  HP-UX does not ship with any such  scripts.	 If  the  customer
       wishes  to use scripts, third party applications such as or can be used.  Alternatively, the shell script can be wrapped in a simple C pro-
       gram that runs the shell script with appropriate permissions:

   What Other Tunable Values Should Be Changed at the Same Time?
       None.

WARNINGS

       None.  All HP-UX kernel tunable parameters are release specific.  This parameter may be removed or  have  its  meaning  changed	in  future
       releases of HP-UX.

       Installation  of  optional  kernel  software, from HP or other vendors, may cause changes to tunable parameter values.  After installation,
       some tunable parameters may no longer be at the default or recommended values.  For information about the effects of installation  on  tun-
       able  values,  consult  the documentation for the kernel software being installed.  For information about optional kernel software that was
       factory installed on your system, see at

FILES

AUTHOR

       was developed by HP.

SEE ALSO

       chmod(1), execve(2), kctune(1M).

							     Tunable Kernel Parameters					     secure_sid_scripts(5)