UNIX for Dummies Questions & Answers

my script is:

Code:

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

Code:

awk '...mycode...' file1.txt >| file2.txt

but it again says:Missing name for redirect!

what is this?

sounds like you are using csh and have noclobber set...e.g.

Code:

% echo $SHELL
/bin/csh
% file ttt
ttt:            cannot open: No such file or directory

% echo hello > ttt

% set noclobber true

% echo world > ttt
ttt: File exists

% unset noclobber 

%  echo world > ttt
% cat ttt
world

(i.e. unset the noclobber variable) ...

HTH

The noclobber is usually more pain than help. It does not protect files from other writers, like "sort -o file_name". It might be good in a production environment, especially if you code your apps so you are writing files with date-time in the name, new each time.

However, removing write permissions, 'chmod a-w file_name' or an equivalent C/PERL call, after writing a final file is even better: more protective, especially if you avoid doing trivial things logged in as root (never a good idea), and yet less restrictive.