piping and redirecting files

shtek · 01-09-2008, 10:23 AM

I want to trim some of the log files and hence i want to do something like

ls -la | grep log

this will give me a list of log files

for each log file I want to do
echo ""> filename

but i need to do it for each file so if i could combine these two command together thats great, bt dont know how..

dive · 01-09-2008, 10:42 AM

something like:

Code:

for log in `ls -la | grep log`
do
echo "" > $log
done

(untested)

ghostdog74 · 01-09-2008, 10:53 AM

use shell expansion

Code:

for log in *log*
do
echo "" > $log
done

colucix · 01-09-2008, 11:28 AM

Just a side note: if the intent of the command

Code:

echo "" > logfile

is to clear the content of the file, you would use one of the following instead

Code:

: > logfile

echo -n > logfile

The former is the "null command", the latter is to avoid the trailing "newline" character. Indeed, if you simply overwrite the file with a zero-length string, the result will be a 1-byte file (and subsequent writes will leave a blank line at the beginning of the file).

shtek · 01-15-2008, 09:39 AM

That worked >!!!!!!