linux-unix

recent posts related to linux and unix

A Linux shell script to rename files with a counter and copy them

As a brief note today, I was recently looking for all Messages/iMessage files that are stored on my Mac, and I used this shell script to copy all of those files — many of which have the same name — into a directory named tmpdir, giving them all new names during the copy process:

count=1
for i in `cat myfiles`
do
    fname=`basename $i`
    cp $i tmpdir/${count}-${fname}
    count=`expr $count + 1`
done

How to use curl to get headers from a URL

Curl FAQ: How do I use curl to get the headers from a website URL?

Short answer: Use curl's -I option, like this:

$ curl -I URL

Here's a specific example, including a real URL and results:

Free Unix/Linux and vi/vim cheat sheets

Way back in the 1990s I created some “cheat sheets” for Unix training classes that I taught. Somewhere in the 2000s I updated them to make sure they worked with Linux as well, Here then are two Unix/Linux cheat sheets I created (way back when) that you can print out if you’re just learning Linux and the vi/vim editor:

Linux crontab examples (every X minutes or hours)

Table of Contents1 - Linux crontab: How to run a command every minute2 - Descriptions of the crontab date/time fields3 - Run a crontab command every hour4 - Run a crontab entry every day5 - Run a crontab entry every 5 minutes6 - Unix and Linux “crontab every” summary7 - Unix and Linux crontab reference information

Linux crontab FAQ: How do I schedule Unix or Linux crontab jobs to run at intervals, like “Every five minutes,” “Every ten minutes,” “Every half hour,” and so on?

Solution: I’ve posted other Unix and Linux crontab tutorials here before (How to edit your Linux crontab file, Example Linux crontab file format), but I’ve never included a tutorial that covers the “every” options, so here are some examples to demonstrate this crontab syntax.

How to install Java, Scala, and SBT on Linux Mint

Lately I’ve been in the process of “making the switch” from macOS to Linux Mint, and to that end, I just installed the Java 8 JDK/SDK, Scala 2.12, and SBT 0.13 on a new Linux Mint system, and I want to note here how I did that while it’s still fresh in my mind. Here are my notes in a compact form.

Teleport: The Unix/Linux ‘cd’ command, improved

Table of Contents1 - The Teleport command2 - Teleport command help3 - For basic use, tp is just like cd4 - Basic teleporting5 - Listing your teleport history6 - Teleport by number7 - Bash completion with Teleport8 - Teleport aliases9 - Adding/creating a teleport alias10 - Using a teleport alias11 - Listing your teleport aliases12 - Removing an alias13 - Teleport command - summary14 - Teleport command - download

Summary: By keeping a history of the directories you've visited, the Teleport command is an improvement on the Unix/Linux cd command. By having a memory, Teleport lets you jump from one directory to any previously visited directory, easily.

January, 2015 Update: The Teleport command now supports Bash completion. For more details on this, see the Github INSTALL.md file.

Notes on how to configure HTTPS/SSL with Nginx

Table of Contents1 - Summary2 - New Linode Server3 - Update Everything4 - Ubuntu Firewall5 - Add a New User6 - Disabling Root Login7 - Limit Login Attempts8 - Install Nginx9 - Adjust Firewall10 - Nginx Configuration11 - NOT what I used: Let’s Encrypt on Ubuntu 16.0412 - (1) Create a cert (openssl)13 - (2) Create a strong Diffie-Hellman group14 - (3) Configure Nginx to Use SSL15 - Adjust the Nginx Configuration to Use SSL16 - (Alternative Configuration) Allow Both HTTP and HTTPS Traffic17 - Adjust the Firewall18 - Enable the Changes in Nginx19 - Test in Browser20 - Nginx "default_server"21 - Can change to a permanent redirect (301)22 - More Security: Preventing Information Disclosure23 - More Security: Fail2Ban24 - Restricting Access by IP Address25 - See also

Without any introduction or discussion, here are the notes I made while learning how to get HTTPS working with Nginx. These are just for me, but if something helps you, cool.

Cerebro, a Spotlight-like launcher for Linux

I recently “made the switch” from MacOS to Linux Mint, and was lamenting the fact that I didn’t have Alfred on Mint. But then this morning I learned about Cerebro, which, if it’s not Alfred yet, at least it’s Spotlight for Linux. omgubuntu.co.uk has this good intro article on Cerebro.

Cerebro is written as an Electron app, and as a result it’s available not only for Linux, but Windows and MacOS as well.

Linux Mint (and Ubuntu): Suspend vs Hibernate (meaning)

When I put Linux Mint on a few of my computers recently I quickly encountered the words “suspend” and “hibernate” when attempting to put a laptop to sleep:

LInux Mint, Suspend vs Hibernate

“What the heck is the difference between Suspend and Hibernate,” I wondered. “I’m used to just having a ‘Sleep’ option on my MacBook Pro.”