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Bash Variables

Here’s how to read Bash variables from another file.

Contents of config.sh

#!/bin/bash
var1='thisisvariableone'
var2='thisisvariabletwo'

Call config.sh from another script.

#!/bin/bash
source config.sh
echo var1
echo var2

This is extremely helpful if you have multiple scripts using a common variable. You just to update one file instead of multiple files. All the other scripts will read and pick up the same variables from a config file. You can use this to setup your global variables.

Split A Large File

How to split a large file. 

split -b 500MB httpd.log
ll -lh
total 1.9G
-rw-r--r-- 1 root root 954M Mar 25 12:35 httpd.log
-rw-r--r-- 1 root root 477M Mar 25 12:38 xaa
-rw-r--r-- 1 root root 477M Mar 25 12:38 xab

Split with an output file.

split -b 200M httpd.log split.log
ll -lh
total 1.9G
-rw-r--r-- 1 root root 954M Mar 25 12:35 httpd.log
-rw-r--r-- 1 root root 200M Mar 25 12:52 split.logaa
-rw-r--r-- 1 root root 200M Mar 25 12:52 split.logab
-rw-r--r-- 1 root root 200M Mar 25 12:52 split.logac
-rw-r--r-- 1 root root 200M Mar 25 12:52 split.logad
-rw-r--r-- 1 root root 154M Mar 25 12:52 split.logae

Convert File to UTF-8

Here’s how to convert multiple files to UTF-8 format.

for file in *.csv; do
    iconv -f ascii -t utf-8 "$file" -o "${file%.txt}.utf8.csv"
done

Matrox Monarch Configuration

You can import the Matrox Monarch HD configuration on boot up from a web page. Go to:

Command Center > Automatic Configuration.
Type in URL Address starting with https.
Check "Load settings on device reboot."
You can either power off the device or hit reset.
Holding reset for more than 5 seconds does a factory reset.
On next bootup, device will have configuration contained from the remote file.

Crontab File

How to load crontab from file.

crontab /path/to/file.txt

Save crontab to a file.

crontab -l > /path/to/file.txt