UNIX Command Line Tools Roundup

Introduction

Most users use Blink Shell to access remote machines, but many don't know that beneath our easy to use interface lies a robust set of command-line tools that would impress even the most proficient UNIX greybeard.

Ever wanted to diagnose a network issue? Sure, there are applications with fancy GUIs for running network analysis, but any UNIX veteran knows that tools like ping and dig are quick and powerful. Want to search through and manipulate your files? grep, awk and sed have you covered. Transfer your command line wizardry to your phone or tablet with Blink Shell.

You can see all the applications at your disposal by pressing TAB on the shell prompt.

File Utilities

iOS limits you to a sandbox, but you can make the most of this by linking files from other locations on your device like iCloud. Simply run link-files to bring up a dialog allowing you to select the folder to connect to Blink Shell.

Once you've linked the desired folder you're ready to go. Want to make folders in iCloud? No problem,

mkdir docs

You can even move files in the cloud with ease,

mv *.pdf docs

Need to find a particular file? Use the power of grep:

grep -nHr TERM LOCATION

We have even included sed and awk! sed is short for stream editor and it allows you to edit text inline, while awk is a superb data reporting and extraction utility.

For example, with sed we can remove any string of characters, in this example we will locate and remove aoe from our file to then form a new file:

sed -i 's/[aoe]//g' file

Need to replace all your potatoes with bananas? Don't worry, we all do that at some point. awk to the rescue!

echo "one potato two potato" | awk '{gsub(/potato/,"banana")}1'

If you want to learn more about sed and awkcheck this fantastic cheatsheet.

Another typical scenario when using a shell is the extraction of a compressed file downloaded from a web browser like Safari. Blink Shell provides tar, gzip and md5 to make this task a breeze.

md5 filename.tar
tar xfz filename.tar -C destination

Blink Shell provides far more utilities and here's a list: awk, bc, cat, chflags, chksum, compress, cp, diff, du, egrep, fgrep, find, gunzip, gzip, head, less, link-files, ln, ls, md5, mv, pwd, rm, rmdir, sed, sort, tail, tar, touch, uncompress, uniq, wc & xargs.

Remote Transfer Tools

Blink Shell offers a lot of useful local functionality but Blink specializes in enabling remote connections and that strength is leveraged in our command line tools. Want to upload a LaTeX file or a generated PDF to your server or even download a file from a Linux machine into iCloud? We have you covered with sftp and scp.

scp file user@remotehost:remotepath
sftp user@remotehost:remotepath

In this example, we will transfer a file named file to the server remotehost with the username of user to place it in the remotepath folder. scp accepts wildcards, allowing the transfer of multiple files at once, but you can also tar the files for a better transfer experience. Blink will

Although the sftp command in UNIX environments is interactive, Blink Shell uses scp and sftp interchangeably. If you wish to start an interactive session, we have a better solution with our Files.app integration. This is a fantastic way to browse and open files in a remote Host.

We heavily recommend using these commands for large uploads and downloads of full directory structures, where the performance is way better than the Files.app, and the commands will offer more visibility and control of the progress

PRO TIP: Blink Shell has an additional flag --update, that will synchronize the contents of source and destination based on timestamps. This is specially useful if you need to keep a folder in sync with the remote. The result is similar to rsync, although rsync has a lot more options and complexity.

Network Diagnostics

The network commands built into Blink Shell can save your day. Have you ever needed to check if a server is up from your phone? Running ping will get the ball rolling, followed with nc for advanced diagnostics.

You'll also find helpful tools like dig and nslookup to troubleshoot DNS issues as well as the ssh command for complex SSH connections and testing.

Have a little downtime? Have some retro fun with telnet:

telnet towel.blinkenlights.nl

We provide a full set of network utilities, including: dig, host, nslookup, ssh, mosh, nc, ping, ping6, rlogin and udptunnel.

Miscellaneous

Blink Shell includes a few extra tools designed to make your mobile life easier.

Perhaps the most essential command is geo. This takes advantage of the device tracking functionality in iOS to enhance security, with the secondary effect of keeping your SSH connections running in the background. Don't worry, your location data won't be sent to Blink. In fact, it isn't sent anywhere.

To enable geo, run:

geo start

To enhance the security of your SSH sessions you can run:

geo lock
# Once you want to stop tracking
geo stop

geo lock will disconnect all active SSH connections if the device is moved significantly, like someone stealing your device. If you only want to enable background tracking for background connections, do:

geo track

Put the clipboard to use on your mobile device with pbpaste and pbcopy. Use the pbcopy command to put the contents of a file into the clipboard and pbpaste to paste the data. You can even use the touch command to create an empty file and paste it with pbpaste clearing your clipboard.

To open a file just run:

open filename

and a dialog will show asking which application to use to open the file.

Finally, use the openurl to launch a website. This is extremely powerful when paired with tools like xargs to open multiple URLs at once.

open url

This whirlwind tour of the Blink Shell just scratches the surface of what you can do with Blink. Go ahead and put your command line chops to use with our innovative command line interface to unlock a whole new world of mobile functionality.