a vs KnockKnock PingPort

a-Shell is a complete local terminal emulator, allowing to run most Unix commands on your iOS device. You can transfer files using scp and curl, edit them with vim and ed, process them using grep, awk and sed. You can work with git repositories using lg2.  Most commands are compiled for iOS native Arm64 format, making them fast and well integrated with the BSD Unix that powers iOS/iPadOS. a-Shell includes Python, Lua, Perl, JavaScript, C, C++ for programming and TeX (texlive 2025, with Tikz and LuaTeX) for text processing. There are also multiple network utilities: nslookup, ping, whois, ifconfig... Type help for help, help -l to get the full list of commands. a-Shell can be controlled from Shortcuts: run commands in order, process files in a-Shell, get the results as text or files, transfer files to other apps... a-shell uses iOS 13+ “multiple windows” ability, so you can run multiple shells at the same time, with different commands, in different directories. You can edit a file in one window with vim and process it in the other with python. Compile your C or C++ programs to webAssembly using clang or clang++, and execute the resulting binary. A complete webAssembly SDK is included (WASI-libc). a-Shell is the complete version. If you need a smaller app, and you don't need a C compiler, a TeX engine, or numpy and matplotlib, there is a-Shell mini.

KnockKnock opens access to your servers with one tap. It sends the knock your firewall expects, a sequence of TCP and UDP ports or ICMP echo requests of agreed sizes, and shows each step as it goes. PORTKNOCK • Name, host (domain, IPv4 or IPv6) and an ordered list of ports, each TCP or UDP • Delay between ports from 0 to 1000 ms to fit your knockd timeout • Progress for every port, and the time of the last knock in the list PINGKNOCK • Ordered groups of ICMP echo requests: count × data size in bytes • The equivalent ping commands, to try the same knock from a terminal • A table of ICMP and IP packet sizes to match your firewall rule, such as iptables -m length or MikroTik packet-size • A warning when VPN or cellular networks may split large packets Works with knockd and any firewall that opens access after a sequence of packets. PRIVATE BY DESIGN • No account, no analytics, no ads, no tracking • Records stay on your iPhone unless you export them, and packets go straight to the hosts you enter FREE AND PRO The free version keeps one PortKnock server and one PingKnock target. KnockKnock Pro, a one-time purchase, removes the limit and lets you export and import your records as a file, to move them to another iPhone. No subscription. Port knocking hides a service but does not replace SSH keys or passwords.