I'm trying to group conditional expressions in zsh.
if [[ ( ! chkchroot ) || ( $# -lt 1 ) ]]; then
echo "usage: $0 [command]"
echo " run this inside a chroot"
return 1
fi
However this fails with a parsing error. Here, chkchroot is a shell function.
In pure POSIX, one can do this.
if [ \( ! chkchroot \) -o \( $# -lt 1 \) ]; then
echo "usage: $0 [command]"
echo " run this inside a chroot"
return 1
fi
Is there a way one can do this with the [[ ]] syntax in zsh?
It sounds like you have a tool chkchroot that you want to run. Your posted code is not how you run commands in an if statement.
To run chkchroot as a command, do not include it inside [[ .. ]]:
if ! chkchroot || [[ $# -lt 1 ]]
then
echo "foo"
fi
Bash interprets your chkchroot as an implicit -n chkchroot (which is always true and does not run chkchroot). Zsh does not allow this, which is why it complains. It's not related to the parentheses.
Related
I need to compare a string partially to check for a given condition.
Like my $1 will be checked if it has a part of a string BLR
while my file input has $1 entries as BLR21 BLR64 IND23
I only need a true condition when $1 is equal to BLR**
where these stars can be anything.
I used a simple if condition
if($1=="BLR21")
{print $2}
Now this only works when whole BLR21 is there in row.
I need to ckeck not for BLR21 but only BLR.
Please Help
Your question is not great, I hope I understood.
Quick and easy solution
grep BLR input.txt
This will output all the lines in which "BLR" is found, in file input.txt. It will match "BLR" with any prefix and suffix, whatever they might be (spaces, alphanumerical, tabs, ...).
"Complicated" solution
A bit more complicated. It does the same thing, but makes sure input.txt exists, and is in the form of a script.
Input file, input.txt:
BLR21 BLR64 IND23
Your script could be:
#!/bin/bash
#
# Arguments
inputfile="input.txt"
if [[ $# -ne 1 ]]
then
echo "Usage: myscript.bash <STRING>"
exit 1
else
string="$1"
fi
# Validation, and processing...
if [[ ! -f "$inputfile" ]]
then
echo "ERROR: file >>$inputfile<< does not exist."
exit 2
else
grep "$string" "$inputfile"
fi
And to call the script, you do:
./myscript.bash BLR
But really, a simple grep does the job here.
Taking it even further...
#!/bin/bash
#
# Arguments
inputfile="input.txt"
if [[ $# -ne 1 ]]
then
echo "Usage: check.bash <STRING>"
exit 1
else
string="$1"
fi
# Validation, and processing...
if [[ ! -f "$inputfile" ]]
then
echo "ERROR: file >>$inputfile<< does not exist."
exit 2
else
while read -r line
do
if [[ "$line" =~ $string ]]
then
echo "$line"
fi
done <"$inputfile"
fi
Now this one is like going to the moon via mars...
It reads each line of the file, one by one. Then it checks if that line contains the string, using the =~ operator inside the if.
But this is crazy, when a simple grep would do.
If the argument is 0 then script should check directory called “App0” is in the windows path variable. If not exists, then add \App0 in the path. I Am Struggling To Understand ( If the argument is 0 ).
My Work So Far.
if [ -d "${Appo}" ]; then
echo "Appo Doesn't Exist."
mkdir Appo
echo "File Created"
fi
Thank You
#!/bin/sh
if [[ $# == 0 ]]
then
echo "zero args"
fi
for arg in "$#" # You might get more than one argument.
do
dir="App${arg}" # Make the name by combining the strings.
if [[ -d $dir ]]
then
echo "App$arg exists"
else
mkdir "$dir" # Be careful the name supplied may contain spaces.
echo "Created directory: $dir"
fi
done
I'm trying to write a function to compare the versions of the products.
my versions can be XX.XX.XX or xx-xx-xx either it's separated with "." or "-"
and number of fields can be different either xx.xx or xx.xx.xx or xx.xx.xx.xx
the versions which im gonna compare will identical in delimiters and with the fields
#!/bin/ksh
set -x
compareVersions ()
{
typeset IFS='.'
typeset -a v1=( $1 )
typeset -a v2=( $2 )
typeset n diff
for (( n=0; n<4; n+=1 )); do
diff=$((v1[n]-v2[n]))
if [ $diff -ne 0 ] ; then
[ $diff -le 0 ] && echo '-1' || echo '1'
return
fi
done
echo '0'
} # ---------- end of function compareVersions ----------
#compareVersions "6100-09-03" "6100-09-02"
compareVersions "6100.09.03" "6100.09.02"
Please check and give me suggestions
I have tried with the below thing which i have got a other post.. but there is no luck.. hope there should some modification should be done. I have to use across platforms ( linux, solaris, AIX ) so i have preferred KSH, i have idea only in shell scripting though.
Create arrays from version strings, then loop through them comparing elements one by one and return values accordingly. The following example will compare two version strings and returns either 0 (versions are equal), 1 (the first version string is greater) or 2 (the second version string is greater).
#!/bin/ksh
function vertest {
set -A av1 `echo $1 | sed -e 's/\'$3'/ /g'`
set -A av2 `echo $2 | sed -e 's/\'$3'/ /g'`
for (( i=0; i < ${#av1[#]}; i++ )) ; do
[[ ${av1[$i]} -eq ${av2[$i]} ]] && continue
[[ ${av1[$i]} -gt ${av2[$i]} ]] && return 1
[[ ${av1[$i]} -lt ${av2[$i]} ]] && return 2
done
return 0
}
v1="2-7-2-1"
v2="1-8-0-1"
vertest $v1 $v2 '-'
exit $?
# end of file.
This example will exit to shell with exit code 1. Should you change $v1 to 1-7-2-1, it will exit to shell with exit code 2. And so on, and so forth.
The separator escaping is not complete, but this works with most reasonable separators like a period (.) and a dash (-). This, as well as parameter checking for the vertest() is left as an exercise for the reader.
When the format of both numbers is equal (leading zero as your example), you can use
compareVersions ()
{
val1=$(echo $1| tr -d ".-")
echo ${val1}
val2=$(echo $2| tr -d ".-")
echo ${val2}
if [ ${val1} -gt ${val2} ] ; then
echo 1
return
fi
if [ ${val1} -eq ${val2} ] ; then
echo 0
return
fi
echo '-1'
} # ---------- end of function compareVersions ----------
I tried to write a script to compile java files with gentoos java-config but i ended up getting an error
zsh: parse error: condition expected: "$1" Can anyone tell me what this means and why it gets reported at line 16 in the function.
function jComp() {
local java_mods = ""
if (( $# == 0)); then
echo "using javac on .java in folder"
`javac *.java`
return 0
elif [[ "$1" == "-h" ]] || [[ "$1" == "--help" ]]; then
echo "Usage: jComp [java modules] [file]"
echo
echo "Options:"
echo " -h, This help message."
echo "modules has to be in the (java-config -l) list"
echo
echo "Report bugs to <tellone.diloom#gmail.com>."
return 0
fi
if [[ "$(java-config -v)" == "" ]]; then
echo "This script depends on java-config"
return 1
elif [[ "$1" =="-d" ]] || [[ "$1" == "--default"]]; then
`javac -cp .:$(java-config -p junit-4) *.java`
if [[ $# == 2 ]]; then
`javac -c .:$(java-config -p junit-4) "$2"`
return 0
fi
fi
while (( $# > 1 )); do
if [[ ! -f "$1" ]]; then
java_mods="$java_mods $1"
shift
continue
fi
done
`javac -cp .:$(java-config $java_mods)`
return 0
}
Links and comment are welcome. Thanks in advance
It looks like your code is trying to compare a string stored in argument $1 to the string -d but the comparison is missing a space after the double equal sign:
elif [[ "$1" =="-d" ]] || [[ "$1" == "--default"]]; then
^
elif [[ "$1" == "-d" ]] || [[ "$1" == "--default"]]; then
I haven't tried the code but, do try and let me know if it solved it !
Btw, it also looks like the second comparison will also fail because of a lack of space before the double square closing brackets:
elif [[ "$1" == "-d" ]] || [[ "$1" == "--default"]]; then
^
elif [[ "$1" == "-d" ]] || [[ "$1" == "--default" ]]; then
All your backticked commands look wrong. You want to run the commands, not interpret their output as a command to run, right? If so, remove all the backticks from the javac invocations.
Then there is a missing space in [[ "$1" =="-d" ]] to make the == a separate token (and another as pointed out by leroyse).
This question already has answers here:
How do I test if a variable is a number in Bash?
(40 answers)
Closed 1 year ago.
How do I check to see if a variable is a number, or contains a number, in UNIX shell?
if echo $var | egrep -q '^[0-9]+$'; then
# $var is a number
else
# $var is not a number
fi
Shell variables have no type, so the simplest way is to use the return type test command:
if [ $var -eq $var 2> /dev/null ]; then ...
(Or else parse it with a regexp)
No forks, no pipes. Pure POSIX shell:
case $var in
(*[!0-9]*|'') echo not a number;;
(*) echo a number;;
esac
(Assumes number := a string of digits). If you want to allow signed numbers with a single leading - or + as well, strip the optional sign like this:
case ${var#[-+]} in
(*[!0-9]*|'') echo not a number;;
(*) echo a number;;
esac
In either ksh93 or bash with the extglob option enabled:
if [[ $var == +([0-9]) ]]; then ...
Here's a version using only the features available in a bare-bones shell (ie it'd work in sh), and with one less process than using grep:
if expr "$var" : '[0-9][0-9]*$'>/dev/null; then
echo yes
else
echo no
fi
This checks that the $var represents only an integer; adjust the regexp to taste, and note that the expr regexp argument is implicitly anchored at the beginning.
This can be checked using regular expression.
###
echo $var|egrep '^[0-9]+$'
if [ $? -eq 0 ]; then
echo "$var is a number"
else
echo "$var is not a number"
fi
I'm kind of newbee on shell programming so I try to find out most easy and readable
It will just check the var is greater or same as 0
I think it's nice way to choose parameters... may be not what ever... :
if [ $var -ge 0 2>/dev/null ] ; then ...
INTEGER
if echo "$var" | egrep -q '^\-?[0-9]+$'; then
echo "$var is an integer"
else
echo "$var is not an integer"
fi
tests (with var=2 etc.):
2 is an integer
-2 is an integer
2.5 is not an integer
2b is not an integer
NUMBER
if echo "$var" | egrep -q '^\-?[0-9]*\.?[0-9]+$'; then
echo "$var is a number"
else
echo "$var is not a number"
fi
tests (with var=2 etc.):
2 is a number
-2 is a number
-2.6 is a number
-2.c6 is not a number
2. is not a number
2.0 is a number
if echo $var | egrep -q '^[0-9]+$'
Actually this does not work if var is multiline.
ie
var="123
qwer"
Especially if var comes from a file :
var=`cat var.txt`
This is the simplest :
if [ "$var" -eq "$var" ] 2> /dev/null
then echo yes
else echo no
fi
Here is the test without any regular expressions (tcsh code):
Create a file checknumber:
#! /usr/bin/env tcsh
if ( "$*" == "0" ) then
exit 0 # number
else
((echo "$*" | bc) > /tmp/tmp.txt) >& /dev/null
set tmp = `cat /tmp/tmp.txt`
rm -f /tmp/tmp/txt
if ( "$tmp" == "" || $tmp == 0 ) then
exit 1 # not a number
else
exit 0 # number
endif
endif
and run
chmod +x checknumber
Use
checknumber -3.45
and you'll got the result as errorlevel ($?).
You can optimise it easily.
( test ! -z "$num" && test "$num" -eq "$num" 2> /dev/null ) && {
# $num is a number
}
You can do that with simple test command.
$ test ab -eq 1 >/dev/null 2>&1
$ echo $?
2
$ test 21 -eq 1 >/dev/null 2>&1
$ echo $?
1
$ test 1 -eq 1 >/dev/null 2>&1
$ echo $?
0
So if the exit status is either 0 or 1 then it is a integer , but if the exis status is 2 then it is not a number.
a=123
if [ `echo $a | tr -d [:digit:] | wc -w` -eq 0 ]
then
echo numeric
else
echo ng
fi
numeric
a=12s3
if [ `echo $a | tr -d [:digit:] | wc -w` -eq 0 ]
then
echo numeric
else
echo ng
fi
ng
Taking the value from Command line and showing THE INPUT IS DECIMAL/NON-DECIMAL and NUMBER or not:
NUMBER=$1
IsDecimal=`echo "$NUMBER" | grep "\."`
if [ -n "$IsDecimal" ]
then
echo "$NUMBER is Decimal"
var1=`echo "$NUMBER" | cut -d"." -f1`
var2=`echo "$NUMBER" | cut -d"." -f2`
Digit1=`echo "$var1" | egrep '^-[0-9]+$'`
Digit2=`echo "$var1" | egrep '^[0-9]+$'`
Digit3=`echo "$var2" | egrep '^[0-9]+$'`
if [ -n "$Digit1" ] && [ -n "$Digit3" ]
then
echo "$NUMBER is a number"
elif [ -n "$Digit2" ] && [ -n "$Digit3" ]
then
echo "$NUMBER is a number"
else
echo "$NUMBER is not a number"
fi
else
echo "$NUMBER is not Decimal"
Digit1=`echo "$NUMBER" | egrep '^-[0-9]+$'`
Digit2=`echo "$NUMBER" | egrep '^[0-9]+$'`
if [ -n "$Digit1" ] || [ -n "$Digit2" ]; then
echo "$NUMBER is a number"
else
echo "$NUMBER is not a number"
fi
fi