#!/bin/bash
SubValue()
{
romanvalue="${romanvalue}$2"
decvalue=$(( $decvalue - $1 ))
}
if [ $decvalue -ge 1000 ] ; then
SubValue 1000 "M"
elif [ $decvalue -ge 900 ] ; then
SubValue 900 "CM"
elif [ $decvalue -ge 500 ] ; then
SubValue 500 "D"
elif [ $decvalue -ge 400 ] ; then
SubValue 400 "CD"
elif [ $decvalue -ge 100 ] ; then
SubValue 100 "C"
elif [ $decvalue -ge 90 ] ; then
SubValue 90 "XC"
elif [ $decvalue -ge 50 ] ; then
SubValue 50 "L"
elif [ $decvalue -ge 40 ] ; then
SubValue 40 "XL"
elif [ $decvalue -ge 10 ] ; then
SubValue 10 "X"
elif [ $decvalue -ge 9 ] ; then
SubValue 9 "IX"
elif [ $decvalue -ge 5 ] ; then
SubValue 5 "V"
elif [ $decvalue -ge 4 ] ; then
SubValue 4 "IV"
elif [ $decvalue -ge 1 ] ; then
SubValue 1 "I"
fi
I tried this code and it gives many errors that
dectoroma.sh: line 13: [: -ge: unary operator expected dectoroma.sh: line 15: [: -ge: unary
operator expected
dectoroma.sh: line 17: [: -ge: unary operator expected
dectoroma.sh: line 19: [: -ge: unary operator expected
dectoroma.sh: line 21: [: -ge: unary operator expected
dectoroma.sh: line 23: [: -ge: unary operator expected
dectoroma.sh: line 25: [: -ge: unary operator expected
dectoroma.sh: line 27: [: -ge: unary operator expected
dectoroma.sh: line 29: [: -ge: unary operator expected
dectoroma.sh: line 31: [: -ge: unary operator expected
dectoroma.sh: line 33: [: -ge: unary operator expected
dectoroma.sh: line 35: [: -ge: unary operator expected
dectoroma.sh: line 37: [: -ge: unary operator expected
could anyone help me to fix this problem please.
The variable decvalue
is not set. You are using variables outside of double quotes then all the commands [ $decvalue -ge... ]
become [ -ge... ]
, thus the error.
You can debug your script using the -x (debug) and/or -v (verbose) option to the line #!/bin/bash -xv
. You'll then see and understand what happens. Instead, you can also call set -xv
to enable debug locally then set +xv
after the lines you want to debug.
Using double quotes, the error message would be a bit more explicit:
bash: [: : integer expression expected
The source of the problem reported in the question is an empty decvalue
as syme has already stated.
Considering the purpose of the script, it seems you attempted to write a recursive function. For this reason, i suggest you to follow the comment under your question by jww regarding debugging!
Moreover, you are encouraged to search for questions on recursive functions in bash on SO. There are excellent answers for factorial computations in bash.
Think about which quantities are "transported" and which are returned/compiled in the end.
If you are really stuck, you find 90% of the solution below.
#!/bin/bash
romanLetters(){
local decvalue=$1
local roman
declare -i decvalue
if [ $decvalue -ge 1000 ]; then
romanvalue="M$(romanLetters $((decvalue - 1000)))"
echo $romanvalue
elif [ $decvalue -ge 900 ]; then
romanvalue="CM$(romanLetters $((decvalue - 900)))"
echo $romanvalue
# ... and so on ...
fi
}
echo "1900: $(romanLetters 1900)"
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