tools

Mon, 01 Jan 0001 00:00:00 +0000

awk#

do an awk thing#

an awk thing

Resources#

some site

Mon, 01 Jan 0001 00:00:00 +0000

awscli#

get details about the credentials used to make this call#

aws sts get-caller-identity

Resources#

Mon, 01 Jan 0001 00:00:00 +0000

bash#

require variables#

REQUIRED_VARS=(
  FOO_VAR
  BAR_VAR
  BAZ_VAR
)

for v in ${REQUIRED_VARS[@]}; do
  if [[ -z "${!v}" ]]; then
    echo "${v} environment variable is not populated"
  fi
done

Resources#

Mon, 01 Jan 0001 00:00:00 +0000

brew#

install a package#

brew install foo

upgrade a package#

brew install foo

remove a package#

brew uninstall foo

Resources#

Homebrew Documentation

Mon, 01 Jan 0001 00:00:00 +0000

curl#

return headers only#

curl -I http://foo.com

download a file using its remote name#

curl -O http://foo.com/bar.txt

download a file and change its name#

curl http://foo.com/bar.txt -o baz.txt

Resources#

Mon, 01 Jan 0001 00:00:00 +0000

git#

add foo#

git add -A  # --all

add bar#

git add -u  # --update

delete merged branch#

git branch -d <branch-name>

force-delete unmerged branch#

git branch -D <branch-name>

rename current branch#

git branch -m <new-branch-name>

create new branch and check it out#

git checkout -b <new-branch>

do cherrypick stuff#

git cherry-pick <commit>

commit with a message#

git commit -m "<message>"

commit foo#

git commit --amend

commit bar#

git commit --fixup

show all unstaged changes#

git diff

?#

git diff <file>

list the files that differ between `main` and the current branch#

git diff main..HEAD --name-only

show some logs#

git log --graph --oneline --decorate

show all the logs#

git log --graph --oneline --decorate --all

#

force the working tree into the state of a given reference#

git reset --hard <ref>

revert the last remote commit#

git reset --hard HEAD^
git push -f

Resources#

Mon, 01 Jan 0001 00:00:00 +0000

jq#

validate and pretty-print a file#

jq . input.json

get a property with raw output#

jq -r .propertyName input.json

minify#

jq -c . < input.json

compare file contents, regardless of structure:#

diff <(jq --sort-keys . a.json) <(jq --sort-keys . b.json)
diff <(jq -S . a.json) <(jq -S . b.json)

Resources#

Mon, 01 Jan 0001 00:00:00 +0000

mysql#

archive a database#

mysqldump --single-transaction <db_name> | gzip -c > YYYYMMDD.sql.tgz

create a local user#

CREATE USER '<user>'@'localhost' IDENTIFIED BY '<password>'; FLUSH PRIVILEGES;

create a network user#

CREATE USER '<user>'@'%' IDENTIFIED BY '<password>'; FLUSH PRIVILEGES;

update a user’s password#

ALTER USER '<user>'@'%' IDENTIFIED BY '<password>'; FLUSH PRIVILEGES;

list the columns in a table#

SHOW COLUMNS FROM (<database>.)<table>;

Mon, 01 Jan 0001 00:00:00 +0000

openssl#

do an openssl thing#

an openssl thing

Resources#

some site

Mon, 01 Jan 0001 00:00:00 +0000

psql#

list databases#

\l

connect to a database#

\c <database_name>

list database tables#

\dt

describe a table#

\d <table_name>
\d+ <table_name> # verbose output

list database schemas#

\dn

list users#

\du
\du <username> # specific user

list functions#

\df

show a function#

\sf <function_name>

edit a function#

\ef <function_name>

list views#

\dv

list installed extensions#

\dx

toggle extended display#

\x

quit `psql`#

\q

Mon, 01 Jan 0001 00:00:00 +0000

python#

run raw Python code directly on the command line#

python -c "print('This is a message from Python!')"

print resolved Python executable’s filepath#

python -c "import sys; print(sys.executable)"

print resolved Python executable’s version#

python -c "import sys; print(sys.version)"

print resolved Python executable’s import path#

python -c "import sys; print('\n'.join(sys.path))"

print Python environment configuration#

python -m site

pretty-print JSON#

python -m json.tool file.json

validate JSON#

cat file.json | python -m json.tool > /dev/null

base64 encode a string#

echo "secret" | python -m base64

base64 decode a string#

echo "c2VjcmV0Cg==" | python -m base64 -d

create and administer a `sqlite3` database#

python -m sqlite3 my.db

test DNS resolution#

python -c "import socket; print(socket.gethostbyname('example.com'))"

run a TCP server on port 9999 that serves `127.0.0.1`#

python -c "import socket as s; sock=s.socket(); sock.bind(('127.0.0.1',9999)); sock.listen(1); print(sock.accept())"

run a TCP server on port 9999 that serves external traffic#

python -c "import socket as s; sock=s.socket(); sock.bind(('0.0.0.0',9999)); sock.listen(1); print(sock.accept())"

run an HTTP server on port 8000 that serves `127.0.0.1`#

python -m http.server 8000

run an HTTP server on port 8000 that serves external traffic#

python -m http.server 8000 --bind 0.0.0.0

run an HTTP server on port 8000 that serves a specific directory#

python -m http.server 8000 --directory /tmp

Mon, 01 Jan 0001 00:00:00 +0000

ssh#

get a key’s SHA256 fingerprint#

ssh-keygen -lf /path/to/key

get a key’s MD5 fingerprint#

ssh-keygen -E md5 -lf /path/to/key

Mon, 01 Jan 0001 00:00:00 +0000

zip#

zip all contents of a directory, preserving directory structure#

zip -r foo.zip path/*

as above, with encryption (prompt for password)#

zip -er foo.zip path/*

as above, providing the password in-line (i.e. in a script)#

zip -er -P my_password foo.zip path/*

tools

awk#

do an awk thing#

Resources#

awscli#

get details about the credentials used to make this call#

Resources#

bash#

require variables#

Resources#

brew#

install a package#

upgrade a package#

remove a package#

Resources#

curl#

return headers only#

download a file using its remote name#

download a file and change its name#

Resources#

git#

add foo#

add bar#

delete merged branch#

force-delete unmerged branch#

rename current branch#

create new branch and check it out#

do cherrypick stuff#

commit with a message#

commit foo#

commit bar#

show all unstaged changes#

?#

list the files that differ between main and the current branch#

show some logs#

show all the logs#

#

force the working tree into the state of a given reference#

revert the last remote commit#

Resources#

jq#

validate and pretty-print a file#

get a property with raw output#

minify#

compare file contents, regardless of structure:#

Resources#

mysql#

archive a database#

create a local user#

create a network user#

update a user’s password#

list the columns in a table#

openssl#

do an openssl thing#

Resources#

psql#

list databases#

connect to a database#

list database tables#

describe a table#

list database schemas#

list users#

list functions#

show a function#

edit a function#

list views#

list installed extensions#

toggle extended display#

quit psql#

python#

run raw Python code directly on the command line#

print resolved Python executable’s filepath#

print resolved Python executable’s version#

print resolved Python executable’s import path#

print Python environment configuration#

pretty-print JSON#

validate JSON#

base64 encode a string#

base64 decode a string#

create and administer a sqlite3 database#

list the files that differ between `main` and the current branch#

quit `psql`#

create and administer a `sqlite3` database#

run a TCP server on port 9999 that serves `127.0.0.1`#

run an HTTP server on port 8000 that serves `127.0.0.1`#