By: Aaron Kili

Aaron Kili — Fri, 10 Feb 2017 09:05:57 +0000

@Cloud Consulting Services

Really nice, it’s a well organized functions library, many thanks for sharing this with us.

By: Cloud Consulting Services

Cloud Consulting Services — Thu, 09 Feb 2017 22:48:52 +0000

Create a function file called myfunctions.sh:
#!/bin/bash # set variables declare -r TRUE=0 declare -r FALSE=1 declare -r PASSWD_FILE=/etc/passwd


##################################################################

# Purpose: Converts a string to lower case

# Arguments:

#   $1 -> String to convert to lower case

##################################################################

function to_lower()

{

    local str="$@"

    local output

    output=$(tr '[A-Z]' '[a-z]'<< Message

#   $2 -> Exit status (optional)

##################################################################

function die()

{

    local m="$1"	# message

    local e=${2-1}	# default exit status 1

    echo "$m"

    exit $e

}

##################################################################

# Purpose: Return true if script is executed by the root user

# Arguments: none

# Return: True or False

##################################################################

function is_root()

{

   [ $(id -u) -eq 0 ] && return $TRUE || return $FALSE

}

################################################################## # Purpose: Return true $user exits in /etc/passwd # Arguments: $1 (username) -> Username to check in /etc/passwd # Return: True or False ################################################################## function is_user_exits() { local u="$1" grep -q "^${u}" $PASSWD_FILE && return $TRUE || return $FALSE }
You can load myfunctions.sh into the current shell environment, enter:

$ .myfunctions.sh
OR
$ ./path/to/myfunctions.sh

Comments on: How To Write and Use Custom Shell Functions and Libraries

By: Aaron Kili

By: Cloud Consulting Services