avoids `expr: warning: ^lts/-[1-9][0-9]*: using ^ as the first character of a basic regular expression is not portable; it is ignored`

Fixes https://github.com/openjs-foundation/security-collab-space/issues/35.

Signed-off-by: zhangdiandian <1635468471@qq.com>

Path lists in environmental variables often give special meaning to
empty entries (e.g. in PATH or MANPATH). These are represented by
leading or trailing colons, or by doubled colons in the middle of the
list.

Adjust the awk invocation to correctly deal with trailing colons by
printing the separator before every field except the first, and then
printing the final separator that is read from the input - this will
either be a colon or the null string. This preserves leading and
trailing colons in all cases while not adding extra colons in the wrong
place.

Add test to confirm the correct behaviour.

Fixes #3144

Co-authored-by: heungjun.park <rockheung@gmail.com>
Co-authored-by: Jordan Harband <ljharb@gmail.com>

See https://unix.stackexchange.com/a/555061/137489

See https://github.com/npm/cli/pull/6674

Signed-off-by: emmanuel-ferdman <35470921+emmanuel-ferdman@users.noreply.github.com>

I had to dig into #2410 to learn about the `PROFILE=/dev/null` technique to install without appending to my shell config. Figured this note would be good to add in the main installation docs.
Also added a note on how to do this as a one-liner which was not obvious for me.

Fixes #3104

Fixes #3035

the `nvm.sh` file assigns and exports an `NVM_CD_FLAGS` variable if it
was sourced from a zsh shell. the fact that it's exported means that
it'll be assigned in all child processes, including the `nvm-exec`
script, which uses bash as the interpreter.

Bash's `cd` command doesn't have a `-q` flag, so if the `NVM_CD_FLAGS`
is assigned `-q`, the script will error out and incorrectly claim that
the node version isn't installed.

this also manifests itself in the `nvm exec` command.

Example:

```console
$ nvm exec 16.14.0 npm --version
Running node v16.14.0 (npm v8.3.1)
/Users/<ME>/.nvm/nvm.sh: line 28: cd: -q: invalid option
cd: usage: cd [-L|[-P [-e]] [-@]] [dir]
both the tree and the node path are required
N/A: version "v16.14.0 -> N/A" is not yet installed.

You need to run "nvm install v16.14.0" to install it before using it.
```

To address this, we unset the `NVM_CD_FLAGS` at the start of the
`nvm-exec` script, before loading `nvm.sh`.

Resolves #3081

travis-ci.org is deprecated and replaced by app.travis-ci.com for a while

Fixes #3054