Few useful UNIX Commands
Find how many jars name ending with examples you have inside location /usr/lib/
#find /usr/lib/ -name "*hadoop*examples*.jar"
To list all the class name inside jar
#find /usr/lib/ -name "hadoop-examples.jar" | xargs -0 -I '{}' sh -c 'jar tf {}'
To search for specific class name inside jar
#find /usr/lib/ -name "hadoop-examples.jar" | xargs -0 -I '{}' sh -c 'jar tf {}' | grep -i wordcount.class
To compress a file using gzip
Below command replaces the original file with file1.txt.gz
$gzip file1.txt
To compress a file using gzip
To retain the original file after zipping, use below command
$gzip -c file1.txt > file1.txt.gz
To view the contents of gzip file without unzipping it
$zcat file1.txt.gz
To compress the contents of folder using gzip
$gzip -r folder
To print environment variables
$printenv
Untar the file
$tar -xzf filename.tar.gz
Unzip the file
$unzip filename.zip
List all members of a group called “dummygroup”:
$awk -F':' '/dummygroup/{print }' /etc/group
List all the groups to which user belongs to: (Ex: dummyuser)
$groups dummyuser
Detect encoding format of the file
$file -i <filename>