Greetings!
I uses bс to make some calculations in my script. For example:
bc
scale=6
1/2
.500000
For further usage in my script I need "0.500000" insted of ".500000".
Could you help me please to configure bc output number format for my case?
In one line:
printf "%0.6f\n" $(bc -q <<< scale=6\;1/2)
Just do all your calculations and output in awk:
float_scale=6
result=$(awk -v scale=$floatscale 'BEGIN { printf "%.*f\n", scale, 1/2 }')
As an alternative, if you'd prefer to use bc and not use AWK alone or with 'bc', Bash's printf supports floating point numbers even though the rest of Bash doesn't.
result=$(echo "scale=$float_scale; $*" | bc -q 2>/dev/null)
result=$(printf '%*.*f' 0 "$float_scale" "$result")
The second line above could instead be:
printf -v $result '%*.*f' 0 "$float_scale" "$result"
Which works kind of like sprintf would and doesn't create a subshell.
Quick and dirty, since scale only applies to the decimal digits and bc does not seem to have a sprintf-like function:
$ bc
scale = 6
result = 1 / 2
if (0 <= result && result < 1) {
print "0"
}
print result;
echo "scale=3;12/7" | bc -q | sed 's/^\\./0./;s/0*$//;s/\\.$//'
I believe here is modified version of the function:
float_scale=6
function float_eval()
{
local stat=0
local result=0.0
if [[ $# -gt 0 ]]; then
result=$(echo "scale=$float_scale; $*" | bc -q | awk '{printf "%f\n", $0}' 2>/dev/null)
stat=$?
if [[ $stat -eq 0 && -z "$result" ]]; then stat=1; fi
fi
echo $result
return $stat
}
Can you put the bc usage into a little better context? What are you using the results of bc for?
Given the following in a file called some_math.bc
scale=6
output=1/2
print output
on the command line I can do the following to add a zero:
$ bc -q some_math.bc | awk '{printf "%08f\n", $0}'
0.500000
If I only needed the output string to have a zero for formatting purposes, I'd use awk.
Related
I'm getting load average in a bash shell script like so
load=`echo $(cat /proc/loadavg | awk '{print $1}')`
I know piping to bc
load=`echo $(cat /proc/loadavg | awk '{print $1}') \> 3 | bc -l`
is used in almost all examples of how to cast $load as an int but this box does not have bc installed and I am not allowed to add it.
I tried
int=`perl -E "say $load - 0"`
I tried
int=${load%.*}
I tried
int=`printf -v int %.0f "$load"`
What I want to be able to do is
if [ "$int" -gt 3.5 ]; then
How do I get that to evaluate as intended?
You can use awk to produce a success/failure depending on the condition:
# exit 0 (success) when load average greater than 3.5, so take the branch
if awk '{ exit !($1 > 3.5) }' /proc/loadavg; then
# load average was greater than 3.5
fi
Unfortunately, since "success" is 0 in the shell, you have to invert the logic of the condition to make awk exit with the required status. Obviously, you can do this in a number of ways, such as changing > to <=.
You don't need any external tools (like awk) to read this stuff. Load average from /proc/loadavg is always formatted with two decimal places, so you can do this:
read load _ < /proc/loadavg
if [ ${load/./} -gt 350 ]; then
# do something
fi
I'm trying to replace numbers from -20 to 30 using sed, but it adds "v" character. What's wrong?
For example: SINR=-18, output must be "c", but output is "vc".
I tryed to delete 1st character, but it returns 1 instead of j.
SINR=`curl -s http://10.0.0.1/status | awk '/3GPP.SINR=/ {print $0}' | awk -F "3GPP.SINR=" '{print $2}'` # returns number
echo $SINR | sed "s/-20/a/;s/-19/b/;s/-18/c/;s/-17/d/;s/-16/e/;s/-15/f/;s/-14/g/;s/-13/h/;s/-12/i/;s/-11/j/;s/-10/k/;s/-9/l/;s/-8/m/;s/-7/n/;s/-6/o/;s/-5/p/;s/-4/q/;s/-3/r/;s/-2/s/;s/-1/t/;s/0/u/;s/1/v/;s/2/w/;s/3/x/;s/4/y/;s/5/z/;s/6/A/;s/7/B/;s/8/C/;s/9/D/;s/10/E/;s/11/F/;s/12/G/;s/13/H/;s/14/I/;s/15/J/;s/16/K/;s/17/L/;s/18/M/;s/19/N/;s/20/O/;s/21/P/;s/22/Q/;s/23/R/;s/24/S/;s/25/T/;s/26/U/;s/27/V/;s/28/W/;s/29/X/;s/30/Y/"
This way would be more elegant and less error-prone:
echo $SINR | awk 'BEGIN { chars="abcdefg" } { print substr(chars, $1 + 21, 1) }'
Of course, chars should contain all the letters you need for the mapping. That is, all the way until ...VWXY as in your example, I just wrote until g to keep it short and sweet.
With this solution your problem disappears.
You don't really need sed or awk if you have bash like you say you do. You can use arrays, which is maybe even less error-prone ;-)
map=({a..z} {A..Z}) # Create map of your characters
SINR=-18 # Set your SINR number to something
SINR=$(($SINR+20)) # Add an offset to get to right place
result=${map[$SINR]} # Lookup your result
echo $result # Print it
c
If you have a mapping process, you're surely better off building a switch statement, a couple of if's, or even using bash associative arrays (bash >= 4.0). For example, you could tackle your problem with the following snippet:
function mapper() {
if [[ $1 -ge -20 && $1 -le 5 ]]; then
printf \\$(printf '%03o' $(( $1 + 117 )) )
elif [[ $1 -ge 6 && $1 -le 30 ]]; then
printf \\$(printf '%03o' $(( $1 + 59 )) )
else
echo ""; return 1
fi
return 0
}
And use like below:
$ mapper -20
a
$ mapper 5
z
$ mapper 6
A
$ mapper 30
Y
$ mapper $SINR
c
echo "${SINR}" | sed 's/-20/a/;t;s/-19/b/;t;s/-18/c/;t;s/-17/d/;t;s/-16/e/;t;s/-15/f/;t;s/-14/g/;t;s/-13/h/;t;s/-12/i/;t;s/-11/j/;t;s/-10/k/;t;s/-9/l/;t;s/-8/m/;t;s/-7/n/;t;s/-6/o/;t;s/-5/p/;t;s/-4/q/;t;s/-3/r/;t;s/-2/s/;t;s/-1/t/;t;s/0/u/;t;s/1/v/;t;s/2/w/;t;s/3/x/;t;s/4/y/;t;s/5/z/;t;s/6/A/;t;s/7/B/;t;s/8/C/;t;s/9/D/;t;s/10/E/;t;s/11/F/;t;s/12/G/;t;s/13/H/;t;s/14/I/;t;s/15/J/;t;s/16/K/;t;s/17/L/;t;s/18/M/;t;s/19/N/;t;s/20/O/;t;s/21/P/;t;s/22/Q/;t;s/23/R/;t;s/24/S/;t;s/25/T/;t;s/26/U/;t;s/27/V/;t;s/28/W/;t;s/29/X/;t;s/30/Y/'
Use the t after s// to accelerate a bit.
vc is normaly not occuring if SINR is just a number like specified
I have two numbers:
value1=686
value2=228.35
I am not able to add an integer and a float. Please help me out to get the result.
I am running it in bash.
echo 1 + 3.5 | bc
awk "BEGIN {print 1+3.5; exit}"
python -c "print 1+3.5"
perl -e "print 1+3.5"
Just replace the numbers with your variables, eg: echo $n1 + $n2 | bc
If you have the bc language installed, you can do the following:
#!bin/bash
numone=1.234
numtwo=0.124
total=`echo $numone + $numtwo | bc`
echo $total
If you don't have bc, then you can try with awk. Just in one single line:
echo 1.234 2.345 | awk '{print $1 + $2}'
There are plenty of other options, also. Like python, perl, php....
Bash doesn't have floating-point types, but you can use a calculator such as bc:
a=686
b=228.35
c=`echo $a + $b | bc`
echo "$c"
#!/bin/Bash
echo "Enter the two numbers to be added:"
read n1
read n2
answer=$(($n1+$n2))
echo $answer
As part of an annotation pipeline for De Novo fish genomes I need to compare e-values from BLAST to see whether they are lower than a certain threshold.
To get the semantics right I first evaluated one of the othet columns in the blast-output, and it works fine like this:
for f in FOLDER/*; do
myVar=$(head -1 $f | awk '{print $4}') ;
if [[ $myVar -gt 50 ]]; then echo ..... ;done
$4 is then a column in the BLAST output with whole numerical values (hit length or something)
However, when I try to change the script to working with the e-values, there is some problems with interpretation of the scientific notation etc...
What I WOULD like is this:
for f in FOLDER/*; do
myVar=$(head -1 $f | awk '{print $11}') ;
if [[ $myVar -gt 1.0e-10 ]]; then echo ..... ;done
where $11 points to the e-value for each hit.
Could this be done in a not to cumbersome manner in bash?
With awk, it is possible:
for f in FOLDER/*; do awk '$11 < 1e-10 {print $11}' "$f"; done
This doesn't need the variable to be defined first.
Greetings!
I uses bс to make some calculations in my script. For example:
bc
scale=6
1/2
.500000
For further usage in my script I need "0.500000" insted of ".500000".
Could you help me please to configure bc output number format for my case?
In one line:
printf "%0.6f\n" $(bc -q <<< scale=6\;1/2)
Just do all your calculations and output in awk:
float_scale=6
result=$(awk -v scale=$floatscale 'BEGIN { printf "%.*f\n", scale, 1/2 }')
As an alternative, if you'd prefer to use bc and not use AWK alone or with 'bc', Bash's printf supports floating point numbers even though the rest of Bash doesn't.
result=$(echo "scale=$float_scale; $*" | bc -q 2>/dev/null)
result=$(printf '%*.*f' 0 "$float_scale" "$result")
The second line above could instead be:
printf -v $result '%*.*f' 0 "$float_scale" "$result"
Which works kind of like sprintf would and doesn't create a subshell.
Quick and dirty, since scale only applies to the decimal digits and bc does not seem to have a sprintf-like function:
$ bc
scale = 6
result = 1 / 2
if (0 <= result && result < 1) {
print "0"
}
print result;
echo "scale=3;12/7" | bc -q | sed 's/^\\./0./;s/0*$//;s/\\.$//'
I believe here is modified version of the function:
float_scale=6
function float_eval()
{
local stat=0
local result=0.0
if [[ $# -gt 0 ]]; then
result=$(echo "scale=$float_scale; $*" | bc -q | awk '{printf "%f\n", $0}' 2>/dev/null)
stat=$?
if [[ $stat -eq 0 && -z "$result" ]]; then stat=1; fi
fi
echo $result
return $stat
}
Can you put the bc usage into a little better context? What are you using the results of bc for?
Given the following in a file called some_math.bc
scale=6
output=1/2
print output
on the command line I can do the following to add a zero:
$ bc -q some_math.bc | awk '{printf "%08f\n", $0}'
0.500000
If I only needed the output string to have a zero for formatting purposes, I'd use awk.