✨ Mastering Bash Special Characters — The Real Power of Linux Terminal 🔥

🔥 Master Bash Special Characters — Power of Linux Terminal

If you work in Linux, DevOps, Cloud, Cyber Security, or Automation, Bash special characters are your superpower.

These symbols control execution, variables, redirection, scripting logic, and automation. Here is the complete cheat-sheet 👇

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✅ Basic Bash Symbols

Symbol	Meaning	Example
$	Variable / Command output	echo $HOME
#	Comment	# comment
*	Wildcard (match all)	*.txt
?	Match one character	file?.log
\	Escape character	echo \"hello\"
~	Home directory	cd ~

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✅ Command Execution Operators

Symbol	Meaning	Example
;	Run sequentially	cmd1; cmd2
&&	Run if previous success	build && deploy
||	Run if previous fails	cd logs || mkdir logs
&	Run in background	sleep 5 &

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✅ Pipes & Redirection

Symbol	Meaning	Example
|	Pipe output	ls | grep txt
>	Output to file (overwrite)	echo hi > file.txt
>>	Append to file	echo hi >> file.txt
<	Redirect input	sort < data.txt

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✅ Advanced Redirection

Symbol	Meaning	Example
<<	Heredoc	cat << EOF
<<<	Here-string	cat <<< "Hello"

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✅ Test & Grouping

Symbol	Meaning	Example
[ ]	Test	[ -f file.txt ]
[[ ]]	Advanced test	[[ $a == $b ]]
( )	Subshell	(cd /tmp && ls)
{ }	Command block	{ echo A; echo B; }

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✅ Brace Expansion

Pattern	Meaning	Example
{1..5}	Number range	echo {1..5}
{a,b}	List	mv f.{txt,backup}

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✅ Special Shell Variables

Variable	Meaning
$?	Last command status
$$	Process ID
$!	Last background PID
$@	All arguments
$#	Argument count

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🎯 Example Script

#!/bin/bash
if [[ -f "$1" ]]; then
  grep "error" "$1" >> logs.txt && echo "Logged ✅"
else
  echo "File not found ❌" && exit 1
fi

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