~bzg/worg

9733cc41342cf710cc1fe97bd3c833ecf796db43 — Max Nikulin 9 days ago 1c6390f
ob-doc-shell.org: Warn concerning optional stdin
1 files changed, 18 insertions(+), 0 deletions(-)

M org-contrib/babel/languages/ob-doc-shell.org
M org-contrib/babel/languages/ob-doc-shell.org => org-contrib/babel/languages/ob-doc-shell.org +18 -0
@@ 159,6 159,24 @@ Run commands in separate shells...[fn:3]
Shell blocks can accept args, work with stdin, be tangled, use noweb,
and more[fn:4].

Some commands try to read standard input if it is available.
In interactive sessions it may be hidden due to time interval between typed
commands, but be careful when they are used in scripts Org source blocks.
[[https://mywiki.wooledge.org/BashFAQ/089][BASH FAQ #89]]
warns concerning =ssh= and =ffmpeg=.  Either explicitly specify
=</dev/null= as input or use here-document syntax.

#+begin_example
ssh example.org 'sed -i -e s/foo/bar/ file.txt' </dev/null
ssh example.org 'tee >>file.log' <<"EOF"
Added by org-babel
EOF
#+end_example

(Quotes around "EOF" delimiter suppress variable expansion in the text.)
Tools may have dedicated options,
for example =ssh -n= is a more concise way to avoid the pitfall.

* Requirements and Setup
# - Installation and configuration of language software
# - Emacs configuration