5-Minutes Guide for Commonly Used Linux Commands

I’m not a serious Linux user, but sometimes I need to use Linux. In a long time, I frequently searched a limited number of Linux commands. So I think it is a good idea to list those frequently-used ones and remember them finally. This definitely improved my work effectiveness.

Here is my list.

1. cp/scp

cp all files with “.extention” as extension to the garget directory.

cp *.extension /target/directory

scp a remote directory to local:

scp -r [email protected]:/path/to/foo /home/user/dir

2. grep

Search ‘keyword’ in a file can be done in one of the following three format:

grep   keyword file
grep  'keyword' file
grep  "keyword" file

Find environment variables that contain ‘keyword”.

env | grep 'keyword'

Recursively search “keyword” in current directory.

grep -r "keyword" *

Recursively search “keyword” in a target directory.

grep -r "keyword" /a/target/directory/

Match only those lines that do NOT contain “keyword”:

grep -v "keyword" /path/to/file

Match only .php files.

grep -r --include=*.php "keyword" ./

Count how many lines of the file contains the keyword.

grep keyword filename | wc -l

3. find

Find the Main.java file in the current directory (including all sub-directories).

find * -name "Main.java"

Find all files (excluding directories) in the current directory (including all sub-directories) whose name contain a keyword.

find ./ -type f -name "*keyword*"

4. zip/unzip

zip all files under current directory.

zip abc.zip *

Unzip all files to current directory.

unzip abc.zip 

Extract a tar using gzip

tar -xzf file.tar.gz

Create a tar using gzip. For example if you are in directory /var/www/html/, and want to zip a directory under /var/www/hmtl, you can use the following command:

tar -czf directory_name.tar.gz directory_name

5. Environment Variable

Set environment variable.

export PROJECT_PATH=/home/name/project/

If a variable already exists, you can connect it with the new value.

export PATH=$PATH:/home/name/project/

If you don’t have root access to a machine, you can not change environment variable permanently. You can put all the variables you want to set in a file. And then run “source”.

source file

6. LAMP Related

Start apache server

sudo /usr/sbin/apache2ctl start

Actually, here I need to remember the apache2ctl. I can use the following to find out where it is:

which apache2ctl

Restart Apache2 on Ubuntu 14

sudo service apache2 restart

Start MySQL

sudo service mysql start

7. Java Development

Install Java: http://www.ubuntugeek.com/how-to-install-oracle-java-7-in-ubuntu-12-04.html
Install Eclipse: http://colinrrobinson.com/technology/install-eclipse-ubuntu/ (Note: last step is to drag the icon to launcher!)

Open GUI file browser via command line

nautilus . &