> For the complete documentation index, see [llms.txt](https://lib.rjo.me/newlib/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://lib.rjo.me/newlib/operating-systems/linux/bash.md).

# Bash

## BASH

### Finding out which Linux Version running

`cat /etc/issues`

### chsh

For some reason when using `chsh -s /bin/bash` I had to restart my computer to take it affect. What nicely worked was `sudo usermod -s /usr/bin/zsh`

### sed

This command substitutes all colons in the PATH to newlines making the echo outpur easier to read

```sh
echo $PATH | sed s/\:/\\n/g
```

#### Replace all http to https in a file

```sh
sed -i 's/http/https/g' /etc/apt/sources.list
```

`-i` for in-place change

#### Append to a line

`sed -i '\|^#AuthorizedKeysFile| s|$| /etc/ssh/authorized_keys/\%u|' sshd_config`\
**-i** means do it in the file on the fly (Do it live)\
**|** means use | as a delimiter for sed, as we have / in the string we want to append\
**^#Auth#** look for for the Line that starts with *#AuthorizedKeysFile* followed by a delimiter\
**s** for replace (substitue)\
**$** for matching the end of the line\
**/etc/ssh** the string we want to append\
**/%u** an escaped %, as *%u* is a variable for user interpreted by ssh\
**sshd\_config** the file we want to change

#### Updating Value in a Yaml File

```sh
sed -i "s/key: .*/key: \"$B64\"/g" file.yaml
```

This updates the Value of **key** with whatever is stored in the Variable **$B64**

### grep

find something recusively **in** the files of a folder `grep <path> -rne <pattern>` -n shows line number -e defines the pattern to look for -r sets recursively See [here](https://stackoverflow.com/questions/16956810/how-do-i-find-all-files-containing-specific-text-on-linux)

### find

Find files in a folder with excluding a path

```sh
find . -path ./exclude/path -prune -o -iname "*pattern*" -print
```

Find all files ending in .md and find the lines that contain django in those files.

```sh
find . -type f -name "*.md" -exec grep "{}" -re django  \;
```

### for loop

Find all Files in current directory where the filesize is bigger the 50Kb and copy them into another directory

```sh
for filename in * ; do size=`wc -l "$filename" | awk '{ print $1 }'` &&  if [ "$size" -gt 50 ]; then cp "$filename" anotherdir; fi;  done
```

Create 10 folders with the number and **\_stringname** as the folder name and do something with all results from find.

```sh
for item in {1..10} ; do mkdir ${item}_stringname ; done
for i in $(find . -iname "*.tf"); do file $i && grep $i -e "ecr" ; done
```

### rename

`rename` uses Perl Regular Expression syntax [cheatsheet](https://perlmaven.com/regex-cheat-sheet) Remove `string` from the beginning of all files in the current directory using `rename`

```sh
rename 's/string//;' 
```

use rename for my kindle exports

```sh
rename 's/[()]//g' *
rename 's/ /_/g' * 
```

rename all files so that *Extra* gets removed and the *number* after it gets prepended to *-other* see grouping and capturing

```sh
45# optiplex in Movies/T/Top Gun (1986)
➜ rename 's/\ Extra\ (\d+)/ $1-other/g' * -n
rename(Top Gun (1986) Extra 10.mkv, Top Gun (1986) 10-other.mkv)
rename(Top Gun (1986) Extra 11.mkv, Top Gun (1986) 11-other.mkv)
rename(Top Gun (1986) Extra 12.mkv, Top Gun (1986) 12-other.mkv)
```

### du

Getting disk usage with excluding one or more pathes

```sh
du --exclude=path1 --exclude=path2 --exclude=path3 -sh *
```

### certbot

I use this to install certbot from letsencrypt on Debian 9.3(stretch) with nginx

```sh
mkdir -p /usr/bin/certbot
cd /usr/bin/certbot
sudo wget https://dl.eff.org/certbot-auto
chmod +x certbot-auto
./certbot-auto --installer nginx
```

Making it update every 2nd month and log into /var/log/certbot/certbot.log

```
mkdir /var/log/certbot
crontab -e
1 1 1 */2 * sh /usr/bin/certbot/certbot-auto renew >> /var/log/certbot/certbot.log 2>&1
```

### turning off screen

Turning off the screen on Linux Mint 18.2 Sonya 4.13.0-41-generic #46\~16.04.1-Ubuntu

```
sudo apt-get install vbetool
sudo vbetool dpms off/on
```

### CommandLine Tools

#### Installing colorls

```sh
sudo apt-get install ruby2.3-dev
sudo gem install colorls
echo "alias colorls='$HOME/.gem/ruby/2.6.0/bin/colorls'" >> ~/.zshrc
echo "alias la='lc -ah'" >> ~/.zshrc
l -lS -r
```

sort Files in reversed order by size, i.e. biggest files on bottome hence easy to see

#### Install bat

Bat is more eye-friendly cat alternative, on [Github](https://github.com/sharkdp/bat). Replace the release number down there with the latest from the Release Page [Release](https://github.com/sharkdp/bat/releases/).

```sh
wget https://github.com/sharkdp/bat/releases/download/v0.16.0/bat_0.16.0_amd64.deb
sudo dpkg -i bat_0.16.0_amd64.deb
echo "alias b=`which batcat`" >> ~/.zshrc
```

#### fuzzyfind

On [fzf](https://github.com/junegunn/fzf)

```sh
sudo apt-get install fzf
```

#### autojump

On [autojump](https://github.com/wting/autojump). Autojump needs to be sourced.

```sh
sudo apt install autojump
echo "source /usr/share/autojump/autojump.sh" >> ~/.zshrc
```

### Pseudo stresstest forkbomb

```sh
t(){for ((i=1; i<=100; i++ )) { (curl www.URL.com > /dev/null  ; echo $i );next} & ; t }
```

Only blows your system without putting real stress on a server, but might get you banned or blocked.

## ZSH

Install, verify `zsh` location and change it to default shell

```
sudo apt-get install zsh
whereis zsh
chsh -s /usr/bin/zsh wolle
```

### Oh-my-zsh

Documentation is [here](https://github.com/ohmyzsh/ohmyzsh) Install `Oh-my-zsh` first because it comes with its own `.zshrc` file

```
sh -c "$(curl -fsSL https://raw.github.com/ohmyzsh/ohmyzsh/master/tools/install.sh)"
```

#### Syntax highlighting

More [here](https://github.com/zsh-users/zsh-syntax-highlighting)

```
git clone https://github.com/zsh-users/zsh-syntax-highlighting.git ${ZSH_CUSTOM:-~/.oh-my-zsh/custom}/plugins/zsh-syntax-highlighting
```

#### Spaceship prompt

To make things look nice, more info [here](https://github.com/spaceship-prompt/spaceship-prompt)

```
git clone https://github.com/spaceship-prompt/spaceship-prompt.git "$ZSH_CUSTOM/themes/spaceship-prompt" --depth=1
ln -s "$ZSH_CUSTOM/themes/spaceship-prompt/spaceship.zsh-theme" "$ZSH_CUSTOM/themes/spaceship.zsh-theme"
```

#### ZSH Completions

more info [here](https://github.com/zsh-users/zsh-completions)

```
  git clone https://github.com/zsh-users/zsh-completions ${ZSH_CUSTOM:-${ZSH:-~/.oh-my-zsh}/custom}/plugins/zsh-completions
```

#### ZSH autosuggestions

See Documentation [here](https://github.com/zsh-users/zsh-autosuggestions/blob/master/INSTALL.md)

```
git clone https://github.com/zsh-users/zsh-autosuggestions ${ZSH_CUSTOM:-~/.oh-my-zsh/custom}/plugins/zsh-autosuggestions
```

### Colorls

Install buildtools, buildessentials, ruby and then a too complicated bash expression that should work independent of ruby version (famous last words).

```
sudo apt-get install build-essential bison openssl libreadline6-dev curl git-core zlib1g zlib1g-dev libssl-dev libyaml-dev libxml2-dev autoconf libc6-dev ncurses-dev automake libtool
sudo apt install ruby ruby-dev gcc make
gem install colorls --user-install
alias colorls="`gem env | grep "USER INSTALLATION DIRECTORY" | awk '{ print $5 }'`/bin/colorls"
```

#### Auto Sugges

## Tmux

Creating a new session `tmux new -s session-name` Leaving/detaching from a session press`<prefix> :` and type `detach` Listing existing sessions `tmux ls` Entering/attaching to an existing session `tmux attach -s session-name/session-number`

### Veracrypt

This downloads Veracrypt from [Vercrypt.fr](https://www.veracrypt.fr/en/Downloads.html) Version 1.23 the latest as of October 2019, unpacks it and installs it. Careful there is some user input neccessary.

```
wget https://launchpad.net/veracrypt/trunk/1.23/+download/veracrypt-1.23-setup.tar.bz2
tar -xf veracrypt-1.23-setup.tar.bz2
sudo bash veracrypt-1.23-setup-gui-x641
```