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Assign top-level JSON entries to shell variables

A recursive version might be useful too. /dev/tty is used to show which shell variables just got defined. Show Sample Output
This is sample output - yours may be different.
```
a="42";
b="s t r i n g";
```
0

json='{"a":42, "b":"s t r i n g", "c": []}' ; eval $(echo $json | jq -r 'to_entries | .[] | select(.value | scalars) | .key + "=\"" + (.value | tostring) + "\";"' | tee /dev/tty)

penthief · 2023-09-26 03:11:38 50
MacOS: Make the terminal app always quit when

When you use the "exit" command in a Linux terminal window, it not only closes the terminal window itself but also the terminal emulator app, such as GNOME Terminal or Konsole, that it belongs to. If you use the "exit" command on macOS, however, Terminal.app still shows a dot below its Dock icon and is still running in the background. This alias, when entered into ~/.zshrc, overrides this behavior.
This is sample output - yours may be different.
-1

alias exit="killall Terminal"

realkstrawn93 · 2023-09-18 04:41:06 85
Get the beats per minute from an audio track

Requires bpm-tools https://www.pogo.org.uk/~mark/bpm-tools/ Show Sample Output
This is sample output - yours may be different.
```
119.900
```
1

ffmpeg -loglevel quiet -i "$AUDIO_FILE" -f f32le -ac 1 -ar 44100 - | bpm

malathion · 2023-09-16 18:55:16 47
Download Video & extract only a specific Time of it

Because this does not download more of the video than necessary, it is faster (especially with long videos).
This is sample output - yours may be different.
0

yt-dlp --external-downloader ffmpeg --external-downloader-args "-ss 00:05:00 -t 00:01:00" "https://www.youtube.com/watch?v=Y6DGABIcB3w"

malathion · 2023-09-16 18:04:12 55
Show temp of all disk

Show temp of all disk with the drivetemp module activate Show Sample Output
This is sample output - yours may be different.
```
WDC WD5000AAKX-0(38°C)
ST500DM002-1BD14(34°C)
WDC WD5000AAKX-0(35°C)
WDC WD80EFZX-68U(37°C)
WDC WD40EFPX-68C(32°C)
WDC WD40EMAZ-51T(31°C)
ST3160811AS     (39°C)
WDC WD40EZRZ-00W(35°C)
SAMSUNG HD501LJ (33°C)
SAMSUNG HD501LJ (35°C)
SAMSUNG HD501LJ (35°C)
SAMSUNG HD501LJ (36°C)
ST3500620AS     (34°C)
ST500DM002-1BD14(35°C)
WDC WD5000AAKS-6(38°C)
```
0

grep -l "drivetemp" /sys/class/hwmon/hwmon*/name | while read f; do printf "%s(%-.2s°C)\n" "`<${f%/*}/device/model`" "`<${f%/*}/temp1_input`"; done

kokoparkletal · 2023-09-10 18:24:29 66

Linux clear restrictions of a user's password

Command that clears the expiration restrictions of a user's password Show Sample Output

chage -E -1 -m 0 -M -1 -W -1 user01

net0bsd · 2023-08-21 06:37:40 168

Monitor changed files into a log file, with day rotation, using fswatch (MacOS)

This command monitors changes in the current folder structure (subfolders included) and files, and log it into a hidden file in the same folder, called `.file_changes_YYMMDD.log`. Modify the `--exclude` parameters to define what should be skipped. Show Sample Output

fswatch --exclude=.git/* --exclude=.settings --event-flags --event-flag-separator=\; -t -f '%Y-%m-%d %H:%M:%S' . >> ./.file_changes_$(date +"%Y-%m-%d" | sed s/-//g).log

paulera · 2023-08-17 23:06:30 126

Compute newest kernel version from Makefile on Torvalds' git repository

The platform-agnostic version of https://www.commandlinefu.com/commands/view/25276/compute-newest-kernel-version-from-makefile-on-torvalds-git-repository because macOS doesn't have wget installed
This is sample output - yours may be different.
1

curl -s -o - https://raw.githubusercontent.com/torvalds/linux/master/Makefile | head -n5 | grep -E '\ \=\ [0-9]{1,}' | cut -d' ' -f3 | tr '\n' '.' | sed -e "s/\.$//"

realkstrawn93 · 2023-08-10 22:25:55 155
Sudoers: bypass all password prompts

If you as the sole user of a computer at home only don’t like needing to repeatedly type a password each time you run a command, using ‘NOPASSWD’ in sudoers for your specific username is for you.
This is sample output - yours may be different.
2

echo "$USER ALL=(ALL:ALL) NOPASSWD: ALL" | sudo tee -a /etc/sudoers

realkstrawn93 · 2023-08-10 22:19:18 112
Prepend section dates to individual entries in a summary log file

Searches for dates on lines by themselves. Uses that date to prepend all rows that contain SEARCHSTRING with the date, until it reaches another line with a date by itself. This fixed an issue with a specific log export where there would be a date, followed by all of the entries for that date.
This is sample output - yours may be different.
5

gawk 'match($0, /^\s*([0-9]{2}\/[0-9]{2}\/[0-9]{4})\s*/, m) {prev_date=m[1]} /SEARCHSTRING/ {print prev_date, ",", $1 $2, ",", $3, "," $5}' inputfile.txt

jtopian · 2023-07-11 23:20:38 411
Print macOS current power delivery max wattage

Print the max wattage of the current power draw source for a Mac. Note that the current amount of watts drawn may be lower, particularly if a high-wattage adapter is plugged into a Mac that has a full battery. Show Sample Output
This is sample output - yours may be different.
```
      Wattage (W): 140
```
1

system_profiler SPPowerDataType | grep Wattage

lgarron · 2023-07-06 17:58:00 191
Create a visually twisted effect by alternating the direction of the "staples" effect vertically. The effect is achieved by moving odd-numbered lines from right to left and even-numbered lines from left to right.

The effect is achieved by moving odd-numbered lines from right to left and even-numbered lines from left to right. For odd-numbered lines (with an index j), the ((j + i) % 2 == 0) condition is satisfied. In this case, the line width is set to i, resulting in the line moving from left to right. For even-numbered lines, the ((j + i) % 2 == 0) condition is not satisfied. The line width is set to $(tput cols) - i, causing the line to move from right to left. This alternating direction of movement creates a twisted visual effect as the lines appear to move in opposite directions. The code runs in a continuous loop, repeatedly updating the lines with changing background colors. There is a slight pause of 0.05 seconds between each iteration to control the speed of the animation.
This is sample output - yours may be different.
1

while :; do for ((i=0;i<$(tput cols);i++));do clear;for ((j=0;j<$(tput lines);j++));do printf "\e[48;5;$((RANDOM%256))m%*s\e[0m\n" $(((j+i)%2?$(tput cols)-i:i)) "";done;sleep 0.05;done;done

Calcutta · 2023-07-04 00:47:37 226
Fill the screen with randomly colored lines

This one-liner fills the screen with randomly colored lines.
This is sample output - yours may be different.
1

while :; do printf "\e[48;2;$((RANDOM % 256));$((RANDOM % 256));$((RANDOM % 256))m%*s\e[0m" $(tput cols) ""; sleep 0.1; done

Calcutta · 2023-07-04 00:38:46 335
Scan LAN and get Windows host names
This is sample output - yours may be different.
1

nmap -sn --system-dns 192.168.0.1-253

swarzynski · 2023-06-23 10:50:25 162
Check if a domain is available for purchase

A quick alias to check if a domain is already registered or if it's available for purchase. Show Sample Output
This is sample output - yours may be different.
```
$ canibuy commandlinefu.com
taken
$ canibuy commandlinekungfu.com
available
```
5

function canibuy { whois "$1" 2>/dev/null | grep -q 'Registrant' && echo "taken" || echo "available" }

tyzbit · 2023-06-21 15:01:25 152
This command provides more color variety for the rainbow-like appearance by generating random color codes from 16 to 231 for adb logcat.
This is sample output - yours may be different.
1

adb logcat|awk '{ i srand();for (i = 1; i <= NF; i++) { color = int(rand() * 216) + 16; printf "\033[38;5;%dm%s\033[0m ", color, $i;} printf "\n"; }'

Calcutta · 2023-05-30 16:48:17 307
Disassemble all ACPI tables on your system

The fact that Linux exposes the ACPI tables to the user via sysfs makes them a gold mine of valuable hardware information for low-level developers. Looping through each of them and disassembling them all makes them even more valuable.
This is sample output - yours may be different.
1

for i in /sys/firmware/acpi/tables/*; do sudo iasl -p $PWD/$(echo $i | cut -d\/ -f6) $i && sudo chown $USER $(echo $i | cut -d\/ -f6); done

realkstrawn93 · 2023-04-16 05:33:51 525
Polkit: Force KDE apps to always recognize your display

KDE apps expect certain variables to be set, and unfortunately pkexec doesn’t set them by default. So, by setting this alias, it becomes possible to run, e.g. “pkexec kate” or “pkexec dolphin” and it’ll actually run.
This is sample output - yours may be different.
2

alias pkexec=“pkexec env DISPLAY=$DISPLAY XAUTHORITY=$XAUTHORITY KDE_SESSION_VERSION=5 KDE_FULL_SESSION=true”

realkstrawn93 · 2023-04-13 05:37:36 293
Loops over files, runs a command, dumps output to a file

In this case I'm selecting all php files in a dir, then echoing the filename and piping it to ~/temp/errors.txt. Then I'm running my alias for PHPCS (WordPress flags in my alias), then piping the PHPCS output to grep and looking for GET. Then I'm piping that output to the same file as above. This gets a list of files and under each file the GET security errors for that file. Extrapolate this to run any command on any list of files and pipe the output to a file. Remove the >> ~/temp/errors.txt to get output to the screen rather than to a file. Show Sample Output
This is sample output - yours may be different.
```
header.php
index.php
page.php
search.php
  19 | ERROR   | [ ] Detected usage of a possibly undefined superglobal array index: $_GET['s']. Use isset() or empty() to check the index exists before using it
  99 | ERROR   | [x] Short PHP opening tag used with echo; expected "<?php echo $_GET ..." but found "<?= $_GET ..."
  99 | ERROR   | [ ] All output should be run through an escaping function (see the Security sections in the WordPress Developer Handbooks), found '$_GET['s']'.
```
0

for f in *php; do echo $f >> ~/temp/errors.txt; phpcsw $f | grep GET >> ~/temp/errors.txt; done

topher1kenobe · 2023-04-12 14:17:14 344
Download Video & extract only a specific Time of it
This is sample output - yours may be different.
1

fmpeg $(yt-dlp -g 'https://de.pornhub.com/view_video.php?viewkey=ph637366806d6eb' | sed 's/^/-ss 00:05 -i /') -t 01:00 -c copy out.mp4

dbiesecke · 2023-04-01 17:39:01 320
urldecode with AWK

Fast and simple awk urldecoder! Note: Parameter -n is specific to GNU awk Show Sample Output
This is sample output - yours may be different.
```
echo -e  "asdf%2Fxx%2Cx\n%2F%2Cxx"  | awk -niord '{printf RT?$0chr("0x"substr(RT,2)):$0}' RS=%..
asdf/xx,x
/,xx
```
1

awk -niord '{printf RT?$0chr("0x"substr(RT,2)):$0}' RS=%..

emphazer · 2023-03-30 15:05:58 305
Create a square thumbnail or favicon using ImageMagick

Resize `file.png` to a 32x32 px image. Use a value other than 32 to create other icon sizes (e.g. 16x16 or 32x32). Combine two favicon sizes using: `convert icon-16px.png icon-32px.png favicon.ico` For a social media preview image, use `2:1#` for the extent and `1200` for the scale.
This is sample output - yours may be different.
8

convert file.png -background transparent -gravity Center -extent 1:1# -scale 32 file-32px.png

lgarron · 2023-03-08 04:11:12 592
List all files in a folder in a git repository by last commit date

This lists all the files in a folder, then finds the commit date for them one by one, then sorts them from newest to oldest
This is sample output - yours may be different.
4

git ls-tree --name-only HEAD foldername/ | while read filename; do echo "$(git log -1 --format="%ci " -- $filename) $filename"; done | sort -r

fivestones · 2023-03-01 17:02:51 252
A Console-based Audio Visualizer for ALSA

# Installing apt search cava sudo apt install cava # modify the default config to change the colors by their hex color code cava -p mkdir ~/.cava nano ~/.cava/config cava # run with changes!
This is sample output - yours may be different.
-2

cava

ioshield · 2023-02-28 19:53:42 331
Speak & Spell-esque glitch sounds

The Speak & Spell's sound chip uses a compressed audio format called "linear predictive coding". This command will read random bytes and attempt to decompress them as if it were audio data compressed in this format, then play it. This results in a unique sound which is similar to a glitching Speak & Spell.
This is sample output - yours may be different.
3

play -tlpc /dev/urandom

Sparkette · 2023-02-16 22:28:16 505
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archlinux:Delete packages from pacman cache that are older than 7 days

Sometimes my /var/cache/pacman/pkg directory gets quite big in size. If that happens I run this command to remove old package files. Packages that we're upgraded in last N days are kept in case you are forced to downgrade a specific package. The command is obviously Arch Linux related.

Detect illegal access to kernel space, potentially useful for Meltdown detection

Based on capsule8 agent examples, not rigorously tested

Take screenshot through SSH

When connected to a box via ssh you can do a quick screenshot of that box using this command. After that you can rscp it over to your box and look at it.

Parallel file downloading with wget

xargs can be used in this manner to download multiple files at a time, and xargs will in this case run 10 processes at a time and initiate a new one when the number running falls below 10.

Recursively execute command on directories (.svn, permissions, etc)

The above command will set the GID bit on all directories named .svn in the current directory recursively. This makes the group ownership of all .svn folders be the group ownership for all files created in that folder, no matter the user. This is useful for me as the subversion working directory on my server is also the live website and needs to be auto committed to subversion every so often via cron as well as worked on by multiple users. Setting the GID bit on the .svn folders makes sure we don't have a mix of .svn metadata created by a slew of different users.

Get the Volume labels all bitlocker volumes had before being encrypted

Get information of volume labels of bitlocker volumes, even if they are encrypted and locked (no access to filesystem, no password provided). Note that the volume labels can have spaces, but only if you name then before encryption. Renaming a bitlocker partition after being encrypted does not have the same effect as doing it before.

Programmatic way to find and set your timezone

Find the package that installed a command

Find out how old a web page is

I used to use the Firefox "View page info" feature a lot to determine how stale the web page I was looking at was. Now that I use mostly Chrome I miss that feature, so here is a command line alternative using wget. The -S says to display the server response, the --spider says to not download any files/pages, just fetch the header. The output goes to stderr, so to grep it you use 2>&1 to combine the stderr stream with stdout, the pipe that to grep for Last-Modified. You can use curl instead if you have it installed, like this: $ curl --head -s http://osswin.sourceforge.net | grep Mod

Startup a VPN connection through command line

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