NoBIGTech Wiki Técnico - docu:csheet:sysadm:script:bash

cr_remove_tr

Anonymous (anonymous@undisclosed.example.com) — 2020-05-09T11:07:14+00:00

Remove ^M CR (carriage return) from output/file ^M is a carriage return (CR), which can be specified as \r for tr or within $'…'. \n specifies a line feed (LF), which is ^J. A Unix line ending is LF, and a Windows line separator is the two-character sequence CR-LF, so Windows text files viewed under a Unix system such as Linux or macOS look like they have ^M at the end of each line except on the last line which is missing its final newline.

expand_aliases

Anonymous (anonymous@undisclosed.example.com) — 2020-02-14T13:15:09+00:00

Expand aliases on a bash script In order to use aliases inside a bash script, we need to issue this command inside a shell: #!/bin/bash shopt -s expand_aliases source ~/.bash_aliases your_alias1 your_alias2

get_script_path

Anonymous (anonymous@undisclosed.example.com) — 2020-09-16T13:37:39+00:00

Get directory of the executed script in bash Simple, straight forward: SCRIPTPATH="$( cd "$(dirname "$0")" >/dev/null 2>&1; pwd -P )"

grep_displayonly

Anonymous (anonymous@undisclosed.example.com) — 2020-03-23T08:41:09+00:00

Use grep text to only highlight it showing original text a_long_text_command | grep --color -E 'YOURSEARCH|$'

hex_convertions

Anonymous (anonymous@undisclosed.example.com) — 2020-09-22T13:58:34+00:00

Convertions and replacements on Linux command line using hex Here is some hex operations you can do with basic or built-in GNU Linux tools: Convert a given string to hex using xxd echo -ne 'your.wanted.string!' | xxd -p Replace a hex string on binary file using

rename_spaces

Anonymous (anonymous@undisclosed.example.com) — 2020-07-27T22:09:42+00:00

Remove spaces from files in a directory recursively Source: Install the package apt-get install rename Rename the dirs first, then the files find -name "* *" -type d | rename 's/ /_/g' find -name "* *" -type f | rename 's/ /_/g'

tcp_raw_bash

Anonymous (anonymous@undisclosed.example.com) — 2020-02-19T14:38:23+00:00

Check a TCP connection and response on raw BASH Sometimes you don't have the proper tools to check connectivity to a site (curl, nc, ping) but you have a bash shell, so you can use bash built-in functions to do this. exec 3<>/dev/tcp/127.0.0.1/8080 && echo -ne 'GET /index.html\n\n' >&3 && cat <&3 2>/dev/null

tcpdump_stdbuf_traffic

Anonymous (anonymous@undisclosed.example.com) — 2020-03-11T09:07:48+00:00

Analyze HTTP traffic with simple command line tools This “simple” and yet effective command will show all the incoming/outgoing HTTP GET and POST plain requests. stdbuf -oL -eL tcpdump -A -s 10240 "tcp port 80 and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0)" | \ egrep -a --line-buffered ".+(GET |HTTP\/|POST )|^[A-Za-z0-9-]+: " | \ perl -nle 'BEGIN{$|=1} { s/.*?(GET |HTTP\/[0-9.]* |POST |HEAD )/\n$1/g; print }'\n

wget_all_website

Anonymous (anonymous@undisclosed.example.com) — 2021-01-13T23:47:54+00:00

Download/Get/Scrap/Crawl all static files from website using Wget We will use the justdeleteme.xyz website as a good example of this usage, because it only contains static files to host everything, but it needs multiple recursive crawls to download pages in all languages.