没有换行符的回声会导致语法错误

Question

I am writing a shell script and I would like to have this code

echo $(awk '{print $1}' /proc/uptime) / 3600 | bc

without the newline character at the end. I wanted to write it using echo -n, but this code

echo -n $(awk '{print $1}' /proc/uptime) / 3600 | bc

results a syntax error:

(standard_in) 1: syntax error

Can you help me with this? Thank you very much!

Answer 1

echo $(awk '{print $1}' /proc/uptime) / 3600 | bc | tr -d "\\n"

备择方案：

echo -n $(($(cut -d . -f 1 /proc/uptime)/3600))

mapfile A </proc/uptime; echo -n $((${A%%.*}/3600))

Answer 2

A solution using echo -n :

echo -n $(echo $(awk '{print $1}' /proc/uptime) / 3600 | bc)

In general, if foo produces a line of output, you can print the same output without a newline using echo -n $(foo) , even if foo is complicated.

A more straightforward solution using pure awk (since awk does arithmetic and output formatting, there's not much point in using both awk and bc ):

awk '{printf("%d", $1 / 3600)}' /proc/uptime