2022-04-06 #

[shell] Generate a randomized, alphanumeric string

$ cat /dev/urandom | LC_ALL=C tr -dc 'a-zA-Z0-9' | head -c 20

2022-02-08 #

[vim] Updating an environment variable in a currently running vim session.

# In the original shell after SSHing in
$ env |grep SSH | sed 's/^/export /g'
export SSH_AUTH_SOCK=/tmp/ssh-abcdefg/agent.2268696

# In the existing vim session running in a tmux session
:let $SSH_AUTH_SOCK = '/tmp/ssh-abcdefg/agent.2268696'

2021-12-13 #

[k8s] Deleting “stuck” resources that reference finalizers. After applying this you should be able to delete the objects, or those that depend on this one.
```
$ kubectl patch {kind}/{name} -p '{"metadata":{"finalizers":[]}}' --type=merge
```

2021-12-02 #

[shell] Using envsubst to template files in shell with GNU gettext utils.

Create a template file with variables using the similar shell syntax:

$ vi tmp.tmpl
my_config_key_1="${MY_CONFIG_KEY_1}"
my_config_key_2="${MY_CONFIG_KEY_2}"

Render the template with envsubst:

$ export MY_CONFIG_KEY_1=tony MY_CONFIG_KEY_2=cesaro
$ envsubst < tmp.tmpl
my_config_key_1="tony"
my_config_key_2="cesaro"

2021-05-29 #

[vim] Convert line indention from 2 to 4 spaces
Convert two-space indents to tabs:
```
:set ts=2 sts=2 noet
:retab!
```
Convert tabs to four-space indents:
```
:set ts=4 sts=4 et
:retab
```

2021-03-15 #

[python3] Merging two dictionaries in Python 3.x.

$ python3
>>> xs = {"a": 1, "b": 2}
>>> ys = {"a": 9, "c": 3}
>>> z = {**xs, **ys}
>>> z
{'a': 9, 'b': 2, 'c': 3}

2021-02-21 #

[nmap-ncat] Execute a command for any connections established to a listening port with the -e option for exec or -c for a command run with /bin/sh.
```
ncat -l 1234 -c "date"
```