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2015-08-20 04:37:09
The following solution reads from a file if the script is called
with a file name as the first parameter $1 otherwise from standard input.
while read line
do
echo "$line"
done < "${1:-/dev/stdin}"
The substitution ${1:-...} takes $1 if defined otherwise
the file name of the standard input of the own process is used.
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Nice, it works. Another question is why you add a quote for it? "${1:-/proc/${$}/fd/0}"
The filename you supply on the command line could have blanks.
Is there any difference between using
/proc/$$/fd/0and/dev/stdin? I noticed the latter seems to be more common and looks more straightforward.Better to add
-rto yourreadcommand, so that it doesn't accidentally eat\chars; usewhile IFS= read -r lineto preserve leading and trailing whitespace.@NeDark: That's curious; I just verified that it works on that platform, even when using
/bin/sh- are you using a shell other thanbashorsh?