X-Files Wiki

Bash Usefull Snippets

Are we root

This line makes sure the user is running the script as root or at least sudo.

[[ $UID -ne 0 ]] && { echo "This script must be run as root or use sudo"; exit 1; }

Are we in the right directory

This checks whether a user is in the right directory before doing something.

directory="test2"; [[ "${PWD##*/}" != "$directory" ]] && { printf "\nWrong directory! Script must be run from $directory\n"; exit 1; }

Alternative method, while shorter it hardcoded directory names in 2 places.

[[ "${PWD##*/}" != "directoryname" ]] && { printf "\nWrong directory! Script must be run from directoryname\n"; exit 1; }

Check Php version example 1

This checks for the current Php version and stores only the version number in a variable.

phpver=$(php -v | awk '/^PHP/ {split($2,a,"."); print a[1]"."a[2]}')

Check Php version example 2

This checks for the current Php version and stores only the version number in a variable no AWK needed.

phpver=$(php -r 'echo PHP_MAJOR_VERSION.".".PHP_MINOR_VERSION;')

Check for yes or no

A snippet that checks for yes and no.

if [ "$answer" != "${answer#[Yy]}" ]; then
    echo Yes
else
    echo No
fi

Output banner and title

A simple snippet that outputs a banner and title.

#
# Color definition
#
red='\033[0;31m' ; bred='\033[1;31m' ; green='\033[0;92m' ; blue='\033[0;36m' ; bold='\033[1m' ; normal='\033[0m'
#
# Function banner
#
banner () {
echo -e "${blue}__  __     _____ _ _"           
echo -e "${blue}\ \/ /    |  ___(_) | ___  ___" 
echo -e "${blue} \  / ___ | |_  | | |/ _ \/ __|"
echo -e "${blue} /  \ ___ |  _| | | |  __/\__ \\"
echo -e "${blue}/_/\_\    |_|   |_|_|\___||___/"
}
#
# Function title
#
title () { printf "\nYour title goes here${normal}\n\n"; }
#
# Execute banner and title
#
banner ; title

Check filesize

Will check for a specific filesize and report back with expected size accordingly.

filename="some-file-name"
filesize=$(stat --printf="%s\n" $filename)
minimum="100000000"
expected=$(( minimum / 1000000 ))
 
if [ "$filesize" -le "$minimum" ]; then
    printf "File $filename is smaller than $expected"mb." aborting...\n\n"
    rm $filename ; exit
else
    printf "File $filename is greater than $expected"mb." continuing...\n\n"
fi

Loop over an array of items

Subject says it all.

#
# Declare array
#
items=(
item1
item2
item3
)
#
# Loop over array and do stuff
#
for i in "${items[@]}" ; do 
echo $i
done

Check sql connections

How to access sql from wihtin bash.

srvstatus=$(systemctl is-active mysqld)
if [[ "$srvstatus" != "active" ]]; then printf "\nMariaDB is not running on this server...\n\n"; exit ; fi ; printf "\n"
 
mysql -e "SELECT DB,USER,HOST,STATE FROM INFORMATION_SCHEMA.PROCESSLIST ORDER BY DB DESC;" ; printf "\n"

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