npm install & gulp copy-assets

[marcos@web526 understrap]$ npm install
npm WARN deprecated express@2.5.11: express 2.x series is deprecated
npm WARN deprecated connect@1.9.2: connect 1.x series is deprecated
npm WARN deprecated minimatch@2.0.10: Please update to minimatch 3.0.2 or higher to avoid a RegExp DoS issue
npm WARN deprecated minimatch@0.2.14: Please update to minimatch 3.0.2 or higher to avoid a RegExp DoS issue
npm WARN deprecated graceful-fs@1.2.3: graceful-fs v3.0.0 and before will fail on node releases >= v7.0. Please update to graceful-fs@^4.0.0 as soon as possible. Use 'npm ls graceful-fs' to find it in the tree.
npm WARN prefer global node-gyp@3.6.2 should be installed with -g

> node-sass@4.5.3 install /home/rafen/webapps/odogramlanding/web/app/themes/understrap/node_modules/node-sass
> node scripts/install.js

Downloading binary from https://github.com/sass/node-sass/releases/download/v4.5.3/linux-x64-48_binding.node
Download complete..] - :
Binary saved to /home/rafen/webapps/odogramlanding/web/app/themes/understrap/node_modules/node-sass/vendor/linux-x64-48/binding.node
Caching binary to /home/marcos/.npm/node-sass/4.5.3/linux-x64-48_binding.node

> node-sass@4.5.3 postinstall /home/rafen/webapps/odogramlanding/web/app/themes/understrap/node_modules/node-sass
> node scripts/build.js

Binary found at /home/rafen/webapps/odogramlanding/web/app/themes/understrap/node_modules/node-sass/vendor/linux-x64-48/binding.node
Testing binary
Binary is fine

> gifsicle@3.0.4 postinstall /home/rafen/webapps/odogramlanding/web/app/themes/understrap/node_modules/gifsicle
> node lib/install.js

  ✔ gifsicle pre-build test passed successfully

> jpegtran-bin@3.2.0 postinstall /home/rafen/webapps/odogramlanding/web/app/themes/understrap/node_modules/jpegtran-bin
> node lib/install.js

  ✔ jpegtran pre-build test passed successfully

> optipng-bin@3.1.4 postinstall /home/rafen/webapps/odogramlanding/web/app/themes/understrap/node_modules/optipng-bin
> node lib/install.js

  ✔ optipng pre-build test passed successfully

> understrap@0.6.5 postinstall /home/rafen/webapps/odogramlanding/web/app/themes/understrap
> gulp copy-assets

[03:41:45] Using gulpfile /home/rafen/webapps/odogramlanding/web/app/themes/understrap/gulpfile.js
[03:41:45] Starting 'clean-source'...
[03:41:45] Finished 'clean-source' after 58 ms
[03:41:45] Starting 'copy-assets'...
[03:41:46] Finished 'copy-assets'"os":"darwin","arch":"any"} (current: {"os":"linux","arch":"x64"})
[marcos@web526 understrap]$ gulp copy-assets
-bash: gulp: command not found