* Marcus Brinkmann said: > > True, but I have to KNOW wheter the feature is supported by the given > > product or not, right? > > Trivial: > > marcus@ulysses[0]:/tmp$ echo -n | wc > 0 0 0 > marcus@ulysses[0]:/tmp$ echo -- -n | wc > 1 2 6 > > Writing a shell fucntion around it which returns yes or no is left as an > exercise to the reader :) Hmm... not quite that good :)). wc is in /usr/bin, that's first. If the test is put in a loop, then we end up with something which unnecessarily slows down the script, just to test whether the feature is supported (I know, nobody should put such a test in a loop :))). > > if [ -n "$POSIX_ECHO_ARG ]; then > > Environment variables for this make me feel uneasy... especially if you want > to use /bin/echo or different echos. The environment variables have the advantage that they don't need another program to test for a feature, access is fast. If you use /bin/echo, then you don't use your shell's builtin - in that case you don't care about the environment. marek
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