Generate a random string - really useful for random passwords for new user creation

cat /dev/urandom | strings --bytes 1 | tr -d '\n\t ' | head -c32

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Conditional awk - for when grep is finding duplicates

My files that contain information about my databases often look like this (It's a dirty way to maintain a database inventory on a server with multiple databases when the database product itself doesn't have a concept of inventory):


Mydatabasename:/path/to/product/home:/path/to/conf/myfile.conf
Anotherdatabasename:/path/to/product/home:/path/to/conf/myfile2.conf


When the database name appears in 2 lines of the file a simple grep would bring back multiple lines:

mydb=$1
DBHome=grep -w $1 ${myfilelistingdbs}| awk -F ":" '{print $2}'



So do THIS instead:

mydb=$1
awk -F ":" -vx=$mydb '$1==x {print $2}' ${myfilelistingdbs}


It says: if the first field matches this then tell me second field contents

this solves problem of db name popping up in a home path

e.g
database_cola:/data/database_pepsi/product:/data/database_pepsi/conf/database_cola.conf
database_pepsi:/data/database_pepsi/product:/data/database_pepsi/conf/database_pepsi.conf


A grep on database_pepsi returned two product homes (and upset my scripts expecting only one line!)
Awk on first field means you only get one product home returned

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How to change the attributes of a file in linux

I often want to change the timestamp of files when testing scripts so I can see whether the logic works with different ages of files etc.

use touch:

touch -a -m -t 201512180130.09 myfile

-a  change the access time
-m change the modification time
-t STAMP use [[CC]YY]MMDDhhmm[.ss] instead of current time

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