examples.md

Syntax examples

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chmod

Make a shell script executable

# add the following to the first line of the file
#!/bin/bash

# run this line to make executable
chmod u+x scriptname.sh

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rsync

File sync / transfer

# transfer to WhaleMap
rsync -rtv file.txt hansen@whalemapvm:/srv/shiny-server/WhaleMap/

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crontab

Automate tasks

# open crontab
crontab -e

# enable edits to crontab
a # this means 'append' in vim

# run every hour
0 * * * * sh /home/hansen/shiny-server/WhaleMap/get_live_dcs.sh

# run every 5 min (usually just for testing)
*/5 * * * * sh /home/hansen/shiny-server/WhaleMap/get_live_dcs.sh

# server side example
0 * * * * /srv/shiny-server/WhaleMap/get_remote_data.sh

# quit and save crontab
:x

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Shiny server

# reload the shiny server
sudo systemctl reload shiny-server
# restart the shiny server
sudo systemctl restart shiny-server

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Cron mail

# Delete
cat /dev/null >/var/mail/hansenjohnson # local
cat /dev/null >/var/mail/hansen # server

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Git

Delete local commits

git reset --hard

Apply patch commit

git am filename

Merge branches (dev into master)

https://git-scm.com/book/en/v2/Git-Branching-Basic-Branching-and-Merging

git checkout master
git merge dev