Command-line expression evaluator
The expr utility evaluates expressions and writes the result on standard output.
See the FreeBSD Man page.
Questions tagged [expr]
102 questions
1
vote
2 answers
How to use `expr` when there's an optional substring in the regex?
I want to find the go[^ ]+ inside these two strings using expr. The output should be 1.17.6 and 1.18-becaeea119.
go version go1.17.6 linux/amd64
go version devel go1.18-becaeea119 Tue Dec 14 17:43:51 2021 +0000 linux/amd64
However, the devel part…
Nato Boram
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1
vote
3 answers
newprime.sh: line 14: [: 0+1: integer expression expected
what's wrong with my code? I am trying to print prime numbers upto n digits
echo Enter Number
read num
for (( i=2; $i <= $num ; i++ ))
do
c=0
for (( j=2; $j <= $i ; j++))
do
…
Sana Mev
- 111
- 8
1
vote
1 answer
How to send form value to node/express to search database?
I've got a pre populated form with gps coordinates and I am trying to search a database.
HMCS
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- 2
1
vote
1 answer
macOS Mojave version 10.14.1 bash-3.2 expr: syntax error
I meet such error:
expr: syntax error
and my script is:
#!/bin/bash
echo `expr index "sarasara" a`
how to fix it.
kailee
- 33
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1
vote
1 answer
ANTLR4 repeating ANDs
With the following rule:
expr:
'(' expr ')' #exprExpr
| expr ( AND expr )+ #exprAnd
| expr ( OR expr )+ #exprOr
| atom #exprAtom
| ID #exprId
;
atom:
'[' ID RELOP INT ']'
;
I would like to allow statements like this:
[a<3] and…
Mike75
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1
vote
1 answer
Why should arithmetic operators be padded by space in expr?
Using expr to evaluate an expression in bash, the following happened
bash-3.2$ expr 1+1
1+1
bash-3.2$ expr 1 + 1
2
Why should the plus sign be padded by space for it to be interpreted as mathematical operation?
mc9
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1
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0 answers
How to send List of Expression to Aggregate Function in Spark JAVA API
I'm trying to execute below code using Spark JAVA api.
sampleDS=sampleDS
.select(col("column1"),col("column2"),col("price1")col("price2"))
.groupBy(col("column1"),col("column2"))
…
John Humanyun
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1
vote
1 answer
TCL ternary expr does processing of output
It involves TCL 8.6, and is derived from answer I got on issue Nitpicking: Tcl storing in a variable or not, for speed, in procedures
So, consider this code:
proc me1 { in1 in2 } {
if { $in1 > $in2 } {
return [ k $in1 ]
} else {
…
user1134991
- 3,003
- 2
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1
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2 answers
How do a test if a parameter is a number in a script using expr?
I've been trying to figure out a way to test if a parameter is a number using the command expr.
In my script so far I've written:
expr $1 + 1 2>/dev/null
if [ $? -eq 2 -o $1 -lt 0 ]
then
echo "$1 is not a positive integer" >&2
exit…
AlexT
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1
vote
1 answer
BSD expr difference with GNU expr
Does any one know why
expr "4" : '-\?[0-9]\+$'
returns 0 on Mac OS X and 1 on Linux?
Fact: Mac uses BSD expr
Linux uses GNU
Sorry, I originally typed
expr "4" : '-\?[0-9]+$'
frankliuao
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- 14
1
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2 answers
what is wrong in this bash expression
I got one error in the first expr
nmin =$(expr ($nr-1)*31)
nmax =$(expr ($nr*31)-1)
array=`ls *d03_*` # specify files to be subsetted
for name in ${array[@]:nmin:30}
After reading the documentation seems like one space or really minor thing…
gis20
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1
vote
2 answers
Why doesn't compiler automatically brace expr?
I was reading through Donal Fellows' excellent explanation on why you should brace your expr.
It makes me wonder why doesn't the tcl compiler automatically brace {} the expr? What are conditions under which this automatic bracing will fail?
Anand
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1
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1 answer
TCSH: convert a sed output to a expr sum
Hi im having troubles with the following code:
#|/bin/tcsh
TOTALMOS=`grep -v "Last MO:" x.log | grep "Total: .* MOs" | grep "Total: .* MOs" | awk '{ print $2 }' | tr '\n' ' ' | awk '{ print $1 }'`
RADIONO=`grep -n "get radio no" x.log | cut -f1…
1
vote
1 answer
Ast parsing of ast.Expr types
There is something I do not understand about the lineno offset that's being calculated by the ast module. Usually when I get the lineno of some ast object, it gives me the first line the object is encountered.
For example in the below case, the…
karpet22
- 51
- 3
1
vote
2 answers
Using Perl to strip everything from a string except HTML Anchor Links
Using Perl, how can I use a regex to take a string that has random HTML in it with one HTML link with anchor, like this:
Whatever Example
and it leave ONLY that and get rid of everything else? No…
Richard Jones
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