Linux Ask! is a Q & A web site specific for Linux related questions. Questions are collected, answered and audited by experienced Linux users.
Exclude files when using the du to estimate disk usage
Answer:
It is easy to use du command to estimate disk usage, however, sometimes you want to ignore some files during the calculation.
To do so, try
# du -h --exclude='*.bak'
The above command will exclude all the file end with the extension .bak during the disk space calculation.
Post a file to a server using the Curl command
Answer:
You can simulate a HTTP form post, with a file being uploaded to a remote server using the curl command.
curl -F 'photo=@/upload/image.jpg' http://example.com/upload.phpAssume the name of the form element of your upload is called "photo"
Debug and verify Postfix configurations
Answer:
A simple way to debug and verify your Postfix configurations is the use the sendmail command with the -bv flag.
Example:
# sendmail -bv username@example.com
No email will be sent using the above command, it just report after verifying each recipient address. This is very useful for testing the Postfix configurations.
Create a transparent image using ImageMagick
Answer:
You can use the following command to create an empty png file, using the ImageMagick.
# convert -size 100x100 xc:none empty.png
an empty png of size 100x100 will be created.
Edit a remote file with vim over SSH
Answer:
If you have a remote file and you can have a quick edit, if you use the following command:
# ssh -t john@remote-server vim /data/test.txt
You will be prompted to login if you don't have proper ssh key in the remote server, and after finishing editing the file, you will quit the ssh session automatically.
