Linux Ask! is a Q & A web site specific for Linux related questions. Questions are collected, answered and audited by experienced Linux users.
How to rename database in MySQL
Answer:
If you are using MyISAM storage engine, the easiest way is to take down the MySQL server and rename the database folder name.
Else, you can use the mysqldump tool, steps as following:
1. Export the database using mysqldump tool
# mysqldump -u root -p old_db > old_db.sql
2. Create a new database
# mysql -u root -p -e 'create database new_db'3. Finally import into the new database
# cat old_db.sql |mysql -u root -p new_dbHow to bulk rename files in Linux
Answer:
Use the rename tool
E.g.
# rename .htm .html *.htm
The above command will rename all *.htm files to *.html files.
wget with rate limiting
Answer:
When you are downloading a large file, and you want to limit the bandwidth used, it is easy with the wget command
wget --limit-rate=100k http://www.example.com/file.zip
The above command will limit the rate to be used not to exceed 100kbps.
Print a particular column data using awk
Answer:
Consider you have a file text.txt like below
1 one
2 two
3 three
How would you only print the second column?
It can be easily done using awk
# awk '{print $2}' text.txt
one
two
three
Try the above command with $1, $2, $3 etc.
How to sort IP addresses in Linux
Answer:
When you have a file ip.txt contains a list of IP addresses, e.g.
127.0.0.2
127.0.0.1
10.10.10.1
To sort it, you can use the following command
# sort -t. -k1,1n -k2,2n -k3,3n -k4,4n ip.txt
10.10.10.1
127.0.0.1
127.0.0.2
