Is this a bug, or something I am doing wrong? Or both? The `xmllint` command (of libxml2 fame) will not open any local files. The `xmlstarlet` command also will usually not open files, I presume because it is relying on libxml2 to open and parse them, but I do not know that. Here is a shell console listing to demonstrate the problem. $ # $ # version of system and xmllint itself $ # $ cat /etc/os-release | NAME="Ubuntu" | VERSION="20.04.1 LTS (Focal Fossa)" | ID=ubuntu | ID_LIKE=debian | PRETTY_NAME="Ubuntu 20.04.1 LTS" | VERSION_ID="20.04" | HOME_URL="https://www.ubuntu.com/" | SUPPORT_URL="https://help.ubuntu.com/" | BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/" | PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy" | VERSION_CODENAME=focal | UBUNTU_CODENAME=focal $ which xmllint | /snap/bin/xmllint $ xmllint --version | /snap/libxml2/69/bin/xmllint: using libxml version 20909-GITv2.9.9 | compiled with: Threads Tree Output Push Reader Patterns Writer SAXv1 FTP HTTP DTDValid HTML Legacy C14N Catalog XPath XPointer XInclude Iconv ISO8859X Unicode Regexps Automata Expr Schemas Schematron Modules Debug Zlib Lzma $ # $ # input document $ # $ cat /tmp/tiny_duck.xml | | | quack | | $ # $ # try it (it fails) $ # $ xmllint --format /tmp/tiny_duck.xml | I/O error : Permission denied | I/O error : Permission denied | warning: failed to load external entity "/tmp/tiny_duck.xml" $ # $ # Could it actually be a permissions problem? $ # No, I just `cat`ted that file. But double-check, $ # anyway. $ # $ ls -l /tmp/tiny_duck.xml | -rw-rw-r-- 1 syd syd 78 Jan 6 08:27 /tmp/tiny_duck.xml $ whoami | syd $ # $ # try a different command that reads and parses XML on same file $ # $ which xmlwf | /usr/bin/xmlwf $ xmlwf -v | xmlwf using expat_2.2.9 | sizeof(XML_Char)=1, sizeof(XML_LChar)=1, XML_DTD, XML_CONTEXT_BYTES=1024, XML_NS $ xmlwf -s -m -d /tmp/ERASE.ME/ /tmp/tiny_duck.xml $ cat /tmp/ERASE.ME/tiny_duck.xml | | | | | | | | | | $ Help *greatly* appreciated, for although I am sure I can live without `xmllint` and `xmlstarlet`, I cannot get any work done without them. I will be forced to revert to 16.04 (or some other earlier release; or some other flavor of GNU/Linux). Thank you.

When	Who	Action	New State
2021-01-06	Manfred Hampl	Answer	Answered
2021-01-06	Syd Bauman	Confirm	Solved

Ubuntulibxml2 package

History of question #694810

Ubuntu
libxml2 package