| Harmful things | Less harmful alternatives |
|---|
| SGML, XML, YAML. | JSON, CSV, ndb(6), plain(UTF-8) text. |
| NFS, SMB, AFS, WebDAV. | 9p. |
| C++, Java, Vala, D, Python, Ruby. | C, Go, Limbo. |
| pthreads (PoSix threads). | CSP-style concurrency: Go, libthread, libtask, Limbo, Erlang, ... |
| Perl, Ruby. | rc, awk. |
| PCRE | Structural Regular Expressions or plain classic/extended regexps (as used in awk, sed, grep, etc.). |
| Bash, tcsh, zsh. | rc, OpenBSD's pdksh, ash/dash. |
| GNU Coreutils. | Plan 9 from User Space. |
| GNU Screen. | tmux. |
| GNU info. | Man pages. |
| GCC. | 8c, tcc. |
| glibc. | ucLibc, DietLibc. |
| GNU autoconf/automake, CMake, imake, scons, waf. | mk, or plain old portable makefiles. |
| Glib. | libc (see above), p9p's C libraries. |
| GTK, Qt, VxWindows. | Tk, textual interfaces. |
| Vim, Emacs, nano, Eclipse, ... | Acme, Sam, ed. |
| UTF-16, UTF-32, Latin-1, other encodings. | UTF-8. | .
| iSCSI, FCoE. | AoE (ATA over Ethernet). |
| PAM (Pluggable Authentication Modules). | Factotum. |
| Jabber and XMPP. | IRC (for IM), STOMP (for general distributed messaging). |
| IMAP. | SMAP(Simple Mail Access Protocol). |
| SQL databases. | Tutorial D, pq, BigTable, plain old hierarchical filesystems. |
| Subversion, aka svn. | Git, Mercurial (aka hg); hell, even CVS or plain old tarballs would be better than svn. |
| FreeBSD, NetBSD, Solaris. | OpenBSD. |
| Apache, lighttpd. | thttpd, OpenBSD's fork of apache 1.3, nginx, or best of all: don't use HTTP. |
| SVG | PS(PostScript) |
| PDF | PS(PostScript), DjVu. |
| EPUB | DjVu. |
| ALSA | OSS4 |
| GPL, LGPL, Apache Software License, MPL, CC. | In order of preference: public domain, ISC, MIT/X, BSD, CC0. |
| head | sed 11q |