commands.txt

# count unique lines
your_command | sort -u | wc -l

# group by count
your_command | sort | uniq -c | sort -nr

# awk select second (or any other) column
awk '{print $2}'

# awk filter by value
awk '{ if ($7 == "yourvalue") { print } }'

# search for text in all files in current folder, case-insensitive
grep -rni your_search_string .

# chromium-headless dump webpage dom to file
chromium-browser --headless  --disable-gpu --dump-dom https://example.com/ > file.html

# check free disk space
df -h

# check disk usage per directory, only one level
du -h --max-depth=1

# remove first line of file
sed '1d' input_file > output_file

# remove every other line (odd, adjust for even)
awk 'NR%2==0' file

# create a timestamp-named tarball (fish shell only)
tar -cvvzf (date "+%Y.%m.%d-%H.%m").tar.gz  source_filename

# connect to mysql database
mysql -u username -h server_ip_or_host -p db_name

# connect to postgresql database
psql -h <host> -p <port> -U <username> -W <password> <database>

# replace strings
sed 's/replace_this/with_this/g'

# trim leading whitespace
sed 's/^[ \t]*//'

# remove blank lines
sed '/^$/d'

# create a file with 1000 lines with an integer between 1 and 10 per line
shuf -i 90-110 -r -n 1000 > file

# HTTP server on specific port for all file in current directory
python -m SimpleHTTPServer 9000

# Display the current date in UTC and ISO 8601 format
date -u +"%Y-%m-%dT%H:%M:%SZ"

# Display the current date as a Unix timestamp (seconds since the Unix epoch)
date +%s

# Display disk usage
df

#Display disk usage with human readable units
df -H