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Solved some security issues #54

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26ec19b
Solved some security issues
spirillen Dec 3, 2023
63641ac
Found more spyware refs
spirillen Dec 3, 2023
6a8e1e7
Update README.md
spirillen Aug 29, 2024
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76 changes: 42 additions & 34 deletions README.md
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Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
# Bash-Oneliner
I am glad that you are here! I was working on bioinformatics a few years ago and was amazed by those single-word bash commands which are much faster than my dull scripts, time saved through learning command-line shortcuts and scripting. Recent years I am working on cloud computing and I keep recording those useful commands here. Not all of them is oneliner, but i put effort on making them brief and swift. I am mainly using Ubuntu, Amazon Linux, RedHat, Linux Mint, Mac and CentOS, sorry if the commands don't work on your system.

This blog will focus on simple bash commands for parsing data and Linux system maintenance that i acquired from work and LPIC exam. I apologize that there are no detailed citation for all the commands, but they are probably from dear Google and Stack Overflow.
This blog will focus on simple bash commands for parsing data and Linux system maintenance that i acquired from work and LPIC exam. I apologize that there are no detailed citation for all the commands, but they are probably from dear search engine and Stack Overflow.

English and bash are not my first language, please correct me anytime, thank you.
If you know other cool commands, please teach me!
Expand Down Expand Up @@ -51,6 +51,7 @@ Ctrl + x + Ctrl + e : launch editor defined by $EDITOR to input your command. Us
Ctrl + z : stop current running process and keep it in background. You can use `fg` to continue the process in the foreground, or `bg` to continue the process in the background.
Ctrl + _ : undo typing.
```

##### Change case
```bash
Esc + u
Expand Down Expand Up @@ -85,7 +86,6 @@ sudo !!
^aaa^bbb^:&
#or
!!:gs/aaa/bbb/

```

##### Run past command that began with (e.g. cat filename)
Expand Down Expand Up @@ -176,12 +176,14 @@ echo "'$foo'"
echo ''$foo''
# bar
```

##### Get the length of variable
```bash
var="some string"
echo ${#var}
# 11
```

##### Get the first character of the variable
```bash
var=string
Expand Down Expand Up @@ -286,15 +288,16 @@ expr 30 \> 20 #1 (true)
```bash
# Number of decimal digit/ significant figure
echo "scale=2;2/3" | bc
#.66

$ .66
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should be # instead of $

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Same as above, it is following your style for returned values. where you uses the # as the shell promt indication, usual this would be the $ sign. Should I replace them all for you to the more used $ or would you keep using the #?


# Exponent operator
echo "10^2" | bc
#100
$ 100
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should be # instead of $

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@spirillen spirillen Aug 29, 2024 •
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By adding a hashtag you would generate a H1 header and not be demonstrating the shell output of the command. And to stick to more common layout for the rest of the document $ should be the right character here

echo "10^2" | bc
$ 100 # returned value from the echo command


# Using variables
echo "var=5;--var"| bc
#4
$ 4
```


Expand All @@ -318,21 +321,25 @@ grep -c "^$"
##### Grep and return only integer
```bash
grep -o '[0-9]*'

#or
grep -oP '\d*'
```
##### Grep integer with certain number of digits (e.g. 3)
```bash
grep '[0-9]\{3\}'

# or
grep -E '[0-9]{3}'

# or
grep -P '\d{3}'
```

##### Grep only IP address
```bash
grep -Eo '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}'

# or
grep -Po '\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}'
```
Expand All @@ -344,6 +351,7 @@ grep -w 'target'
#or using RE
grep '\btarget\b'
```

##### Grep returning lines before and after match (e.g. 'bbo')
```bash
# return also 3 lines after match
Expand Down Expand Up @@ -976,7 +984,7 @@ cat grep_list |xargs -I{} grep {} filename

##### Xargs and sed (replace all old ip address with new ip address under /etc directory)
```bash
grep -rl '192.168.1.111' /etc | xargs sed -i 's/192.168.1.111/192.168.2.111/g'
grep -rl '192.0.2.1' /etc | xargs sed -i 's/192.0.2.1/192.0.2.2/g'
```


Expand Down Expand Up @@ -1249,7 +1257,7 @@ emacs -nw --eval '(org-mode)' --insert <(curl https://raw.githubusercontent.com/

##### Download all from a page
```bash
wget -r -l1 -H -t1 -nd -N -np -A mp3 -e robots=off http://example.com
wget -r -l1 -H -t1 -nd -N -np -A mp3 -e robots=off http://example.net

# -r: recursive and download all links on page
# -l1: only one level link
Expand All @@ -1259,7 +1267,7 @@ wget -r -l1 -H -t1 -nd -N -np -A mp3 -e robots=off http://example.com
# -N: turn on timestamp
# -nd: no parent
# -A: type (separate by ,)
# -e robots=off: ignore the robots.txt file which stop wget from crashing the site, sorry example.com
# -e robots=off: ignore the robots.txt file which stop wget from crashing the site, sorry example.net
```

##### Upload a file to web and download (https://transfer.sh/)
Expand All @@ -1275,7 +1283,7 @@ curl https://transfer.sh/tG8rM/filename.txt -o filename.txt
##### Download file if necessary
```bash
data=file.txt
url=http://www.example.com/$data
url=http://www.example.net/$data
if [ ! -s $data ];then
echo "downloading test data..."
wget $url
Expand All @@ -1284,17 +1292,17 @@ fi

##### Wget to a filename (when a long name)
```bash
wget -O filename "http://example.com"
wget -O filename "http://example.net"
```

##### Wget files to a folder
```bash
wget -P /path/to/directory "http://example.com"
wget -P /path/to/directory "http://example.net"
```

##### Instruct curl to follow any redirect until it reaches the final destination:
```bash
curl -L google.com
curl -L example.net
```

## Random
Expand Down Expand Up @@ -1387,11 +1395,11 @@ xcowsay
3. evince filename.pdf
```

##### Use google-chrome browser from ssh server
##### Use google-chrome browser from ssh server (Spyware, so don't)
```bash
1. ssh -X user_name@ip_address
2. apt-get install libxss1 libappindicator1 libindicator7
3. wget https://dl.google.com/linux/direct/google-chrome-stable_current_amd64.deb
3. wget https://dl.example.net/linux/direct/google-chrome-stable_current_amd64.deb
4. sudo apt-get install -f
5. dpkg -i google-chrome*.deb
6. google-chrome
Expand Down Expand Up @@ -1649,7 +1657,7 @@ uname -i

##### Surf the net
```bash
links www.google.com
links www.example.net
```

##### Add user, set passwd
Expand Down Expand Up @@ -2444,38 +2452,38 @@ ipmitool -I bmc lan set 1 defgw ipaddr 192.168.0.1

##### Resolve a domain to IP address(es)
```bash
dig +short www.example.com
dig +short www.example.net

# or
host www.example.com
host www.example.net
```

##### Get DNS TXT record a of domain
```bash
dig -t txt www.example.com
dig -t txt www.example.net

# or
host -t txt www.example.com
host -t txt www.example.net
```

##### Send a ping with a limited TTL to 10 (TTL: Time-To-Live, which is the maximum number of hops that a packet can travel across the Internet before it gets discarded.)
```bash
ping 8.8.8.8 -t 10
ping 192.0.2.1 -t 10
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@dibs dibs Sep 16, 2024 •
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I don't think this packet would travel across the internet but it would with 8.8.8.8

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by using the RFC:5737 TEST-NET-1 network address 192.0.2.1 you are not promoting any trackers/spyware or any other malicious address. By mention any particular DNS recursor, would only end up in a religious war or mistrust on the idea for this cheat sheet. This is why I changed the bad resolver to a "fictive" address for neutrality.

```

##### Print the route packets trace to network host
```bash
traceroute google.com
traceroute example.net
```

##### Check connection to host (e.g. check connection to port 80 and 22 of google.com)
##### Check connection to host (e.g. check connection to port 80 and 22 of example.net)
```bash
nc -vw5 google.com 80
# Connection to google.com 80 port [tcp/http] succeeded!
nc -vw5 example.net 80
# Connection to example.net 80 port [tcp/http] succeeded!

nc -vw5 google.com 22
# nc: connect to google.com port 22 (tcp) timed out: Operation now in progress
# nc: connect to google.com port 22 (tcp) failed: Network is unreachable
nc -vw5 example.net 22
# nc: connect to example.net port 22 (tcp) timed out: Operation now in progress
# nc: connect to example.net port 22 (tcp) failed: Network is unreachable
```

##### Nc as a chat tool!
Expand All @@ -2499,13 +2507,13 @@ nmap -p0-65535 localhost
##### Check if a host is up and scan for open ports, also skip host discovery.
```bash
#skips checking if the host is alive which may sometimes cause a false positive and stop the scan.
$ nmap google.com -Pn
$ nmap example.net -Pn

# Example output:
# Starting Nmap 7.01 ( https://nmap.org ) at 2020-07-18 22:59 CST
# Nmap scan report for google.com (172.217.24.14)
# Nmap scan report for example.net (172.217.24.14)
# Host is up (0.013s latency).
# Other addresses for google.com (not scanned): 2404:6800:4008:802::200e
# Other addresses for example.net (not scanned): 2404:6800:4008:802::200e
# rDNS record for 172.217.24.14: tsa01s07-in-f14.1e100.net
# Not shown: 998 filtered ports
# PORT STATE SERVICE
Expand All @@ -2522,12 +2530,12 @@ $ nmap -A -T4 scanme.nmap.org

##### Look up website information (e.g. name server), searches for an object in a RFC 3912 database.
```bash
whois google.com
whois example.net
```

##### Show the SSL certificate of a domain
```bash
openssl s_client -showcerts -connect www.example.com:443
openssl s_client -showcerts -connect www.example.net:443
```

##### Display IP address
Expand Down Expand Up @@ -2577,7 +2585,7 @@ hostnamectl set-hostname "mynode"

##### Find out the web server (e.g Nginx or Apache) of a website
```bash
curl -I http://example.com/
curl -I http://example.net/
# HTTP/1.1 200 OK
# Server: nginx
# Date: Thu, 02 Jan 2020 07:01:07 GMT
Expand All @@ -2593,7 +2601,7 @@ curl -I http://example.com/

##### Find out the http status code of a URL
```bash
curl -s -o /dev/null -w "%{http_code}" https://www.google.com
curl -s -o /dev/null -w "%{http_code}" https://www.example.net
```

##### Unshorten a shortended URL
Expand Down