What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
Bash scripting lets you combine terminal commands with variables, decisions, loops, functions, and input/output redirection. You can start with a short script that repeats a command or checks whether a file exists, then build toward larger tasks as you learn how Bash interprets your text.
This guide walks through those basics and points to free Bash cheat sheets for quick lookups. Examples are illustrations, not tested code; try them in a safe directory and adapt them to your system.
What Bash is and how a script runs
A shell is a program that accepts commands and runs them. Bash—short for the Bourne Again SHell—is both a command interpreter and a shell language. Alongside running commands, it provides features such as variables, functions, expansions, conditional statements, loops, and redirections. The GNU Bash Reference Manual, edition 5.3, documents these features and how Bash executes scripts.
A Bash script is a text file containing commands for Bash to interpret. For example, a script can group commands you would otherwise enter one at a time. A minimal illustration is:
Free tools Windows power users keep installed
One-click scans. No signup required.
#1 Best Overall
- Read Before You Buy — No Video Output: These adapters support charging and USB 2.0 data transfer, but cannot transmit video signals. Except for standard USB webcams (which use USB data only), they are not compatible with HDMI/DisplayPort cables, video-capable USB-C hubs, or docking stations with video output.
- Convert USB-A Ports to USB-C: Designed to connect USB-C earphones, cables, flash drives, card readers, and other USB-C accessories to standard USB-A ports. Plug-and-play with no drivers or software required.
- Aluminum Alloy Housing: Built with a sturdy aluminum alloy shell that aids in heat dissipation and protects against daily wear and scratches. Designed to maintain a stable and secure connection.
- Compact & Travel-Friendly: The ultra-compact design allows the adapter to stay plugged into your device without blocking adjacent ports or adding bulk, reducing wear and tear on your original USB ports.
- 12-Month Warranty: Backed by a 12-month manufacturer warranty for peace of mind. Designed to meet strict quality control standards for reliable everyday performance.
#!/usr/bin/env bash
printf 'Hello, terminaln'The first line is commonly called a shebang; it indicates which interpreter should run the file when the operating system launches it as a program. You can also run a script by passing its filename to Bash, for example bash hello.sh. File permissions and available commands can affect whether a script runs successfully.
Variables and parameter expansion
Variables let you give a value a name and use that value later. Assignment and expansion are different operations: assignment sets a value, while expansion substitutes the value into a command or another piece of text.
name="Sam"
printf 'Hello, %sn' "$name"There must be no spaces around the equals sign in an assignment. In name="Sam", Bash assigns the text to the variable; in "$name", the dollar sign asks Bash to expand the variable’s value. The quotes around the expansion help keep the value together as one argument if it contains spaces.
Rank #2
- 5-in-1 USB-C Hub: Experience comprehensive connectivity featuring a Power Delivery input, two USB-A 2.0 ports, a USB-A 3.0 port, and an HDMI port. (Note: The USB-C power delivery input port is only for connecting an external wall charger to power your laptop and cannot power peripheral devices.)
- 90W Pass-Through Charging: Achieve optimal charging with 90W pass-through power to your laptop, supported by a total input of 100W, with the hub reserving 10W for operational efficiency. (Note: Wall charger not included.)
- Quick Data Transfers: Accelerate your productivity with rapid data transfers using a high-speed 5Gbps USB 3.0 port and two 480Mbps USB 2.0 ports.
- 4K HDMI Display: Enhance your visual experience with a hub capable of delivering 4K resolution at 30Hz in both mirror and extend modes. Please note that this hub is compatible with MacBook (macOS 12 and newer), Windows 10 and 11, ChromeOS, and laptops equipped with DP Alt Mode and Power Delivery. Note: This device is not compatible with Linux.
- What You Get: Anker USB-C Hub (5-in-1, 4K HDMI), welcome guide, 18-month warranty, and our friendly customer service.
Quoting and special characters
Characters such as spaces, dollar signs, and quotation marks can have special meaning to Bash. Quoting controls whether Bash interprets those characters or treats them more literally. The GNU manual describes quoting as a way to remove special meaning from characters or words and prevent certain interpretations, including parameter expansion.
The Tool Desk
Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →- Double quotes generally preserve spaces while allowing parameter expansion:
"$name"expands the variable. - Single quotes preserve the enclosed text literally:
'$name'is the characters dollar sign andname, not the variable’s value. - Unquoted text may undergo additional interpretation, including word splitting and filename expansion. Quote variable expansions when you want their value treated as one argument.
For example, printf '%sn' "$name" is safer for a value that could contain spaces than writing printf '%sn' $name.
Conditionals and loops
Make a decision with an if statement
A conditional runs different commands depending on whether a test succeeds. This illustration checks whether a named path is a regular file:
Rank #3
- Sleek 7-in-1 USB-C Hub: Features an HDMI port, two USB-A 3.0 ports, and a USB-C data port, each providing 5Gbps transfer speeds. It also includes a USB-C PD input port for charging up to 100W and dual SD and TF card slots, all in a compact design.
- Flawless 4K@60Hz Video with HDMI: Delivers exceptional clarity and smoothness with its 4K@60Hz HDMI port, making it ideal for high-definition presentations and entertainment. (Note: Only the HDMI port supports video projection; the USB-C port is for data transfer only.)
- Double Up on Efficiency: The two USB-A 3.0 ports and a USB-C port support a fast 5Gbps data rate, significantly boosting your transfer speeds and improving productivity.
- Fast and Reliable 85W Charging: Offers high-capacity, speedy charging for laptops up to 85W, so you spend less time tethered to an outlet and more time being productive.
- What You Get: Anker USB-C Hub (7-in-1), welcome guide, 18-month warranty, and our friendly customer service.
file="notes.txt"
if [[ -f "$file" ]]; then
printf 'Found %sn' "$file"
else
printf 'No regular file at %sn' "$file"
fiThe [[ -f "$file" ]] test succeeds when the path refers to a regular file. A different test is needed for directories or other conditions.
Repeat work with a loop
A for loop processes a list of values; a while loop repeats while a condition succeeds. This small illustration prints two names:
for name in Ada Linus; do
printf 'Hello, %sn' "$name"
doneUse loops when the same operation should be applied to multiple items. When working with filenames, take care with spaces and special characters; quoting and choosing an appropriate way to enumerate files matters.
Rank #4
- Dual Converters, Infinite Potential：Includes 2× USB C male to USB A female adapters and 2× USB A male to USB C female adapters. Perfect for a wide range of uses—tablets with Bluetooth keyboards, expand USB ports on macbook, and more. Two different converters for all your daily needs
- Next-Level 10Gbps & 3A Charging: No more slow 480Mbps, this usb to usb c adapter has a transfer speed of up to 10Gbps, allowing you to do more transferring in less time. This usb adapter fits both USB A and USB C charger, supporting up to 3A fast charging
- Upgraded Exquisite Craftsmanship: With an aluminum alloy housing and metal connector, the usbc to usb adapter is extremely durable and sturdy. Rigorously tested to withstand more than 10,000 times of plugging and unplugging, ensuring long-lasting performance
- Broad Compatible: The usb c to usb adapter widely supports all USB C/ USB A devices like laptops, tablets, cellphones, car chargers, and phone chargers. Such as compatible with MacBook Pro/Air 2023/2022, Thunderbolt 4/3 Devices,Apple MagSafe Watch 9/8/7/SE/Ultra, iPad Pro 2022/2021, Samsung Galaxy S23/S20/S10, and iPhone 17/16/15 Pro. Plug and play
- Please Note: To reach 10Gbps speed, keep the cable under 3.3 ft. For USB A Male to USB C adapters, try flipping the USB C connector. USB C Male to USB A adapters support bidirectional 10Gbps transfer within 3.3 ft
Functions for reusable commands
A function groups commands under a name so you can invoke them more than once. This illustration defines a greeting function that uses its first argument:
greet() {
printf 'Hello, %sn' "$1"
}
greet "Sam"Within a function, $1 refers to its first positional argument. Functions make repeated logic easier to organize, but they do not automatically isolate commands or protect against unsafe input.
Redirection: control input and output
By default, commands usually read input from the terminal and write output there. Redirection changes where that input or output goes. For example, > sends standard output to a file, replacing its existing contents, while >> appends standard output. The < operator supplies a file as standard input.
Quick wins for a faster PC:
Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →Clear out junk files and repair common Windows errorsFree Scan →Best Value
- 5-in-1 Connectivity: Equipped with a 4K HDMI port, a 5 Gbps USB-C data port, two 5 Gbps USB-A ports, and a USB C 100W PD-IN port. Note: The USB C 100W PD-IN port supports only charging and does not support data transfer devices such as headphones or speakers.
- Powerful Pass-Through Charging: Supports up to 85W pass-through charging so you can power up your laptop while you use the hub. Note: Pass-through charging requires a charger (not included). Note: To achieve full power for iPad, we recommend using a 45W wall charger.
- Transfer Files in Seconds: Move files to and from your laptop at speeds of up to 5 Gbps via the USB-C and USB-A data ports. Note: The USB C 5Gbps Data port does not support video output.
- HD Display: Connect to the HDMI port to stream or mirror content to an external monitor in resolutions of up to 4K@30Hz. Note: The USB-C ports do not support video output.
- What You Get: Anker 332 USB-C Hub (5-in-1), welcome guide, our worry-free 18-month warranty, and friendly customer service.
printf 'Run completedn' > run.log
printf 'Another runn' >> run.logBe especially careful with >: it can overwrite a file. Redirection is a core Bash feature, but what a command writes to standard output versus standard error depends on that command.
Free Bash cheat sheets and the official manual
A cheat sheet is useful for looking up syntax; it is not a replacement for learning how Bash interprets it. For authoritative explanations, start with the GNU manual. Its landing page says the manual is available in HTML, PDF, Info, ASCII, and other formats, and was last updated July 4, 2025. The current reference page identifies Bash Reference Manual edition 5.3, updated May 18, 2025.
| Resource | Best for | Format and scope |
|---|---|---|
| GNU Bash manual | Learning Bash behavior from the official project documentation | Full manual in HTML, PDF, Info, ASCII, and other formats; landing page last updated July 4, 2025 |
| GNU Bash Reference Manual | Detailed reference on commands, quoting, control structures, functions, expansions, redirections, and scripts | Edition 5.3; updated May 18, 2025 |
| Red Hat Bash shell cheat sheet | Quick syntax lookup with examples | Web page with a downloadable cheat sheet; check the page for current download options |
| Linuxize Bash cheatsheet | Quick reference for variables, conditionals, loops, and functions | Web page with PDF download/print options; the page reports an update date of August 17, 2026 |
For a beginner’s own one-page reference, prioritize variable assignment and expansion, quoted arguments, if tests, for and while loops, functions, and redirection. Download options and page contents can change, so check the linked pages for what is currently available.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
