Overwrite


 
Thread Tools Search this Thread
Top Forums UNIX for Dummies Questions & Answers Overwrite
# 8  
Old 03-26-2001
OK. Now it is clear. You want to overwrite an existing file with data from another file. Wheeew! I feel better now Smilie

Strange, I never get a 'file exists' error in KSH and my problem is that I sometimes overwrite files I shouldn't have Smilie

Example (as root) in KSH:

Code:
# echo hello > a
# echo world > b
# cat b > a
# cat a
world

Interesting. Perhaps you are getting the error because you don't have permissions to write over the file?
# 9  
Old 03-26-2001
what is the noclobber variable? what does it do?

BTW, thx PXT, it worked!

Neo: indeed I have permissions to write over the file as I can delete, append etc...and now with >| i can overwrite : )

thanks everyone!
# 10  
Old 03-27-2001
Quote:
what is the noclobber variable? what does it do?

If you turn on the noclobber option with "set noclobber" then redirecting to an existing file using the > should produce an error. In csh/tcsh this can be overridden on a case-by-case basis with >!, in bash/ksh it is >|

In csh/tcsh you also have the &gt;&gt;! syntax. If noclobber is set, and you use &gt;&gt; to append to a file, you will get an error if the file does <I>not exist</I> (can't append to a non-existant file). If you use &gt;&gt;! you will override this behaviour, and create the file if it does not already exist. I dont believe that bash or ksh have this feature (file is always created if it does not exist).

noclobber is a handy option if you tend to frequently overwrite files that you intended to keep. See the relevant manual page for your shell to learn more about this and other options.



[Edited by PxT on 03-27-2001 at 12:34 AM]
 
Login or Register to Ask a Question

Previous Thread | Next Thread

9 More Discussions You Might Find Interesting

1. SCO

Command line overwrite

is there a way to overwrite what I have typed in rather than having to hit enter and re enter the command? SCO UNIX 3.2.4.2 (14 Replies)
Discussion started by: steveo314
14 Replies

2. UNIX for Dummies Questions & Answers

[Solved] Suppress do you wish to overwrite (y or n)?

Hi all, as i have to deal every day with .log and also .csv files, i would like to know if there is any way to suppress "do you wish to overwrite (y or n)?" prompt with the option no for all prompts, the command i usually run is the following, find... (2 Replies)
Discussion started by: charli1
2 Replies

3. Shell Programming and Scripting

Better to Delete or Overwrite

Hello All, I had just a question about my Bash Script I'm currently writing. The script I have writes some text to a output file. After I write to the output file I send the file to another server to do some stuff with it. After the file sends in the script, I don't need the output/txt... (4 Replies)
Discussion started by: mrm5102
4 Replies

4. Shell Programming and Scripting

overwrite only if both files are the same size

Dear users, I've been looking for a way to overwrite files only if both have the same size, how could I do this? any help is very appreciated. Best regards, Gery (5 Replies)
Discussion started by: Gery
5 Replies

5. UNIX for Advanced & Expert Users

linux overwrite directory

How do you overwrite a directory with another directory? I know you can delete your directory then copy your directory over, but I would think there would be a way to do this in one step. (5 Replies)
Discussion started by: cokedude
5 Replies

6. UNIX for Dummies Questions & Answers

overwrite problem

my script is: awk '...mycode...' file1.txt > file2.txt and i want to overwrite file2.txt eachtime I run this script. but it says:File exists! :( I have tried awk '...mycode...' file1.txt >| file2.txt but it again says:Missing name for redirect! :confused::confused: what is this? (2 Replies)
Discussion started by: gc_sw
2 Replies

7. Shell Programming and Scripting

sed command to overwrite

Hi, i have a file ver.sql with the following contents , Here i need to put a in the next line of END statment . So iam doing the following D:\>type ver.sql begin ctxsys.driimp.set_value('STOP_WORD','yours'); ctxsys.driimp.set_object('STORAGE','BASIC_STORAGE',2);... (1 Reply)
Discussion started by: mhdmehraj
1 Replies

8. Shell Programming and Scripting

Files overwrite in awk

Hi guys, I checked the knowledge base before posting this question. is there any way by which you can ALWAYS ALLOW file overwrite in AWK?. i.e. an option similar to noclobber in Korn shell. I don't to check for files existence and remove them. (1 Reply)
Discussion started by: Moon Noon
1 Replies

9. UNIX for Dummies Questions & Answers

overwrite problem

Hi im using the following to copy a file to a directory, the user being prompted to overwrite if the file already exists in that directory, cp -i myfile /home/brief/bin2 but this reveals the path of the directory when being prompted to overwrite (below) cp: overwrite... (2 Replies)
Discussion started by: ali999
2 Replies
Login or Register to Ask a Question