This question already has answers here:
How to handle more than 10 parameters in shell
(2 answers)
Closed 3 years ago.
I have got the following code snippet.
if [ "$2" == "azure" ] && [ -n $11 ]; then
CRED_KIND=$2
CRED_NAME=$3
CRED_UNAME=$4
CRED_PWD=$5
TWR_UNAME=$6
TWR_PWD=$7
CLNT=$8
SEC=$9
SUBS=$10
TEN=$11
credsplaybook $CRED_KIND $CRED_NAME $CRED_UNAME $CRED_PWD $TWR_UNAME $TWR_PWD $CLNT $SEC $SUBS $TEN
exit 1
fi
For some reason, even when i pass only 7 arguments, it keeps executing the if condition considering only first check and skips the second one. As per the condition, it should check if the second argument is "azure" and whether a total of 11 arguments are passed.
./createResourcesPlaybook.sh cred azure test123 myuser mypass tower towerpass
[INFO] Creating Playbook for Credential with type azure
.
.
.
rest of output
[ "$2" == "azure" ] && [ -n $11 ] are two unrelated commands chained together, the second only is executed if the first is "true".
Also, and as mentioned by others, double-digit (or more) positional argument variables needs to be enclosed in braces. So $11 needs to be ${11}.
And the -n option to the test command ([ is an alias of test) is to check if a string is empty or not but if ${11} doesn't exist then it's not equal to an empty string but rather nothing at all, making the -n check invalid.
To solve both these problems use the -a option for logical and of two conditions, and use double-quotes to make ${11} a string:
if [ "$2" == "azure" -a -n "${11}" ]
Related
This question already has answers here:
How can I store a command in a variable in a shell script?
(12 answers)
Dynamic variable names in Bash
(19 answers)
Closed 1 year ago.
I am running different program with different config. I tried to convert string (kmeans and bayes) in the inner loop to variables I defined at the beginning, so I can run the programs and capture the console output. kmeans_time and bayes_time are used to record execution time of each program.
#!/bin/bash
kmeans="./kmeans -m40 -n40 -t0.00001 -p 4 -i inputs/random-n1024-d128-c4.txt"
bayes="./bayes -t 4 -v32 -r1024 -n2 -p20 -s0 -i2 -e2"
kmeans_time=0
bayes_time=0
for n in {1..10}
do
for prog in kmeans bayes
do
output=($(${prog} | tail -1))
${$prog + "_time"}=$( echo $kmeans_time + ${output[1]} | bc)
echo ${output[1]}
done
done
However, I got the following errors. It seems that the prog is executed as a string instead of command I defined. Also, concatenation of the time variable filed. I've tried various ways. How is this accomplished in Bash?
./test.sh: line 11: kmeans: command not found
./test.sh: line 12: ${$app + "_time"}=$( echo $kmeans_time + ${output[1]} | bc): bad substitution
What I am trying to do is to execute as follow, which can work properly.
kmeans="./kmeans -m40 -n40 -t0.00001 -p 4 -i inputs/random-n1024-d128-c4.txt"
output=($($kmeans | tail -1))
# output[1] is the execution time
echo "${output[1]}"
kmeas_times=$kmeans_times+${output[1]}
I want to iterate over different programs and calculate each of their average execution time
I am vaguely guessing you are looking for printf -v.
The string in bayes is not a valid command, nor a valid sequence of arguments to another program, so I really can't guess what you are hoping for it to do.
Furthermore, output is not an array, so ${output[1]} is not well-defined. Are you trying to get the first token from the line? You seem to have misplaced the parentheses to make output into an array; but you can replace the tail call with a simple Awk script to just extract the token you want.
Your code would always add the value of kmeans_time to output; if you want to use the variable named by $prog you can use indirect expansion to specify the name of the variable, but you will need a temporary variable for that.
Mmmmaybe something like this? Hopefully this should at least show you what valid Bash syntax looks like.
kmeans_time=0
bayes_time=0
for n in {1..10}
do
for prog in kmeans bayes
do
case $prog in
kmeans) cmd=(./kmeans -m40 -n40 -t0.00001 -p 4 -i inputs/random-n1024-d128-c4.txt);;
bayes) cmd=(./bayes -t 4 -v32 -r1024 -n2 -p20 -s0 -i2 -e2);;
esac
output=$("${cmd[#]}" | awk 'END { print $2 }')
var=${prog}_time
printf -v "$var" %i $((!var + output))
echo "$output"
done
done
As an alternative to the indirect expansion, maybe use an associative array for the accumulated time. (Bash v5+ only, though.)
If running the two programs alternatingly is not important, your code can probably be simplified.
kmeans () {
./kmeans -m40 -n40 -t0.00001 -p 4 -i inputs/random-n1024-d128-c4.txt
}
bayes () {
./bayes -t 4 -v32 -r1024 -n2 -p20 -s0 -i2 -e2
}
get_output () {
awk 'END { print $2 }'
}
loop () {
time=0
for n in {1..10}; do
do
output=("$#" | get_output)
time=$((time+output))
print "$output"
done
printf -v "${0}_time" %i "$time"
}
loop kmeans
loop bayes
Maybe see also http://mywiki.wooledge.org/BashFAQ/050 ("I'm trying to put a command in a variable, but the complex cases always fail").
Following output consisting of several devices needs to be parsed:
0 interface=ether1 address=172.16.127.2 address4=172.16.127.2
address6=fe80::ce2d:e0ff:fe00:05 mac-address=CC:2D:E0:00:00:08
identity="myrouter1" platform="MikroTik" version="6.43.8 (stable)"
1 interface=ether2 address=10.5.44.100 address4=10.5.44.100
address6=fe80::ce2d:e0ff:fe00:07 mac-address=CC:2D:E0:00:00:05
identity="myrouter4" platform="MikroTik" version="6.43.8 (stable)"
3 interface=ether4 address=fe80::ba69:f4ff:fe00:0017
address6=fe80::ba69:f4ff:fe00:0017 mac-address=B8:69:F4:00:00:07
identity="myrouter2" platform="MikroTik" version="6.43.8 (stable)"
...
10 interface=ether5 address=10.26.51.24 address4=10.26.51.24
address6=fe80::ba69:f4ff:fe00:0039 mac-address=B8:69:F4:00:00:04
identity="myrouter3" platform="MikroTik" version="6.43.8 (stable)"
11 interface=ether3 address=10.26.51.100 address4=10.26.51.100
address6=fe80::ce2d:e0ff:fe00:f00 mac-address=CC:2D:E0:00:00:09
identity="myrouter5" platform="MikroTik" version="6.43.8 (stable)"
edit: for ease of things I shortened and anonymized the output, first block has 7 lines, second block has 5 lines, third block has 7 lines, fourth block 4 lines, so the number of lines is inconsistent.
Basically its the output from a Mikrotik device: "/ip neighbor print detail"
Optimal would be to access every device(=number) on its own, then further access all setting=value (of one device) seperately to finally access settings like $device[0][identity] or similar.
I tried to set IFS='\d{1,2} ' but seems IFS only works for single character seperation.
Looking on the web I didn't find a way to accomplish this, am I looking for the wrong way and there is another way to solve this?
Thanks in advance!
edit: Found this solution Split file by multiple line breaks which helped me to get:
devices=()
COUNT=0;
while read LINE
do
[ "$LINE" ] && devices[$COUNT]+="$LINE " || { (( ++COUNT )); }
done < devices.txt
then i could use #Kamil's solution to easily access values.
While your precise output format is a bit unclear, bash offers an efficient way to parse the data making use of process substitution. Similar to command substitution, process substitution allows redirecting the output of commands to stdin. This allows you to read the result of a set of commands that reformat your mikrotik file into a single line for each device.
While there are a number of ways to do it, one of the ways to handle the multiple gymnastics needed to reformat the multi-line information for each device into a single line is by using tr and sed. tr to first replace each '\n' with an '_' (or pick your favorite character not used elsewhere), and then again to "squeeze" the leading spaces to a single space (technically not required, but for completeness). After replacing the '\n' with '_' and squeezing spaces, you simply use two sed expressions to change the "__" (resulting from the blank line) back into a '\n' and then to remove all '_'.
With that you can read your device number n and the remainder of the line holing your setting=value pairs. To ease locating your "identity=" line, simply converting the line into an array and looping using parameter expansions (for substring removal), you can save and store the "identity" value as id (trimming the double-quotes is left to you)
Now it is simply a matter of outputting the value (or doing whatever you wish with them). While you can loop again and output the array values, it is just a easy to pass the intentionally unquoted line to printf and let the printf-trick handle separating the setting=value pairs for output. Lastly, you form your $device[0][identity] identifier and output as the final line in the device block.
Putting it altogether, you could do something like the following:
#!/bin/bash
id=
while read n line; do ## read each line from process substitution
a=( $line ) ## split line into array
for i in ${a[#]}; do ## search array, set id
[ "${i%=*}" = "identity" ] && id="${i##*=}"
done
echo "device=$n" ## output device=
printf " %s\n" ${line[#]} ## output setting=value (unquoted on purpose)
printf " \$device[%s][%s]\n" "$n" "$id" ## $device[0][identity]
done < <(tr '\n' '_' < "$1" | tr -s ' ' | sed -e 's/__/\n/g' -e 's/_//g')
Example Use/Output
Note, the script takes the filename to parse as the first input.
$ bash mikrotik_parse.sh mikrotik
device=0
interface=ether1
address=172.16.127.2
address4=172.16.127.2
address6=fe80::ce2d:e0ff:fe00:05
mac-address=CC:2D:E0:00:00:08
identity="myrouter1"
platform="MikroTik"
version="6.43.8
(stable)"
$device[0]["myrouter1"]
device=1
interface=ether2
address=10.5.44.100
address4=10.5.44.100
address6=fe80::ce2d:e0ff:fe00:07
mac-address=CC:2D:E0:00:00:05
identity="myrouter4"
platform="MikroTik"
version="6.43.8
(stable)"
$device[1]["myrouter4"]
device=3
interface=ether4
address=fe80::ba69:f4ff:fe00:0017
address6=fe80::ba69:f4ff:fe00:0017
mac-address=B8:69:F4:00:00:07
identity="myrouter2"
platform="MikroTik"
version="6.43.8
(stable)"
$device[3]["myrouter2"]
Look things over and let me know if you have further questions. As mentioned at the beginning, you haven't defined an explicit output format you are looking for, but gleaning what information was in the question, this should be close.
I think you're on the right track with IFS.
Try piping IFS=$'\n\n' (to break apart the line groups by interface) through cut (to extract the specific field(s) you want for each interface).
Bash likes single long rows with delimter separated values. So first we need to convert your file to such format.
Below I read 4 lines at a time from input. I notices that the output spans over 4 lines only - I just concatenate the 4 lines and act as if it is a single line.
while
IFS= read -r line1 &&
IFS= read -r line2 &&
IFS= read -r line3 &&
IFS= read -r line4 &&
line="$line1 $line2 $line3 $line4"
do
if [ -n "$line4" ]; then
echo "ERR: 4th line should be empt - $line4 !" >&2
exit 4
fi
if ! num=$(printf "%d" ${line:0:3}); then
echo "ERR: reading number" >&2
exit 1
fi
line=${line:3}
# bash variables can't have `-`
line=${line/mac-address=/mac_address=}
# unsafe magic
vars=(interface address address4
address6 mac_address identity platform version)
for v in "${vars[#]}"; do
unset "$v"
if ! <<<"$line" grep -q "$v="; then
echo "ERR: line does not have $v= part!" >&2
exit 1
fi
done
# eval call
if ! eval "$line"; then
echo "ERR: eval line=$line" >&2
exit 1
fi
for v in "${vars[#]}"; do
if [ -z "${!v}" ]; then
echo "ERR: variable $v was not set in eval!" >&2
exit 1;
fi
done
echo "$num: $interface $address $address4 $address6 $mac_address $identity $platform $version"
done < file
then I retrieve the leading number from the line, which I suspect was printed with printf "%3d" so I just slice the line ${line:0:3}
for the rest of the line I indent to use eval. In this case I trust upstream, but I try to assert some cases (variable not defined in the line, some syntax error and similar)
then the magic eval "$line" happens, which assigns all the variables in my shell
after that I can use variables from the line like normal variables
live example at tutorialspoint
Eval command and security issues
This is more directed to learning about BASH rather than creating a specific code.
---Problem: Write a Bash script that takes a list of login names on your computer system as command line arguments, and displays these login names, full names and user-ids of the users who own these logins (as contained in the /etc/passwd file), one per line. If a login name is invalid (not found in the /etc/passwd file), display the login name and an appropriate error message. ---
If I needed to create a code to fulfill this problem could I do it using a "choice" list like this:
read -p "Enter choice: " ch
if [ "$ch" = "1" ]; then
function_1
else
if [ "$ch" = "2" ]; then
function_2
else
if [ "$ch" = "3" ]; then
function_3
else
if [ "$ch" = "4" ]; then
function_4
else
if [ "$ch" = "5" ]; then
function_5
fi x5
or would it have to be completed using a grep and test method where by the user read input must be taken into variables Name1 Name2.... NameN and are tested to the ect/passwd file via grep command.
#!/bin/bash
# pgroup -- first version
# Fetch the GID from /etc/group
gid=$(grep "$̂1:" /etc/group | cut -d: -f3)
# Search users with that GID in /etc/passwd
grep "^[^:]*:[^:]*:[^:]*:$gid:" /etc/passwd | cut -d: -f1`enter code here`
Please explain the best you can with some generic code. I am still learning the basics and testing different ideas. I apologize if these are very vague concepts, I am still getting the hang of BASH.
You would:
Accept (read) from the user the username,
Check if the username exists by retrieving the record using grep,
If positive result (i.e. you got data), display it as needed,
Otherwise, display an error message (or whatever you need).
You are almost there (got how to get input, how to search using grep). What you need is to get the result of the grep into a variable that you can check. You may try something like:
Result=$(grep....)
and then check the contents of Result.
To me it looks like you're missing an important part of the problem: the names are passed as arguments to the script:
./script.sh name1 name2 name3
If this is the case, then a loop would be the most appropriate thing to use:
for login; do
printf '%s: %s\n' "$login" "$(grep "^$login" /etc/passwd)"
done
Note that a for loop iterates over the list of arguments passed to the script $# by default.
Would like to read multiple values from a property file using a shell script
My properties files looks something like below, the reason I added it following way was to make sure, if in future more students joins I just need to add in in the properties file without changing any thing in the shell script.
student.properties
total_student=6
student_name_1="aaaa"
student_name_2="bbbb"
student_name_3="cccc"
student_name_4="dddd"
student_name_5="eeee"
When I run below script I not getting the desired output, for reading the student names from properties file
student.sh
#!/bin/bash
. /student.properties
i=1
while [ $i -lt $total_student ]
do
{
std_Name=$student_name_$i
echo $std_Name
#****** my logic *******
} || {
echo "ERROR..."
}
i=`expr $i + 1`
done
Output is something like this
1
2
3
4
5
I understand the script is not getting anything for $student_name_ hence only $i value is getting printed.
Hence, wanted to know how to read values from the properties file.
You can do variable name interpolation with ${!foo}. If $foo is "bar", then ${!foo} gives you the value of $bar. In your code that means changing
std_Name=$student_name_$i
to
var=student_name_$i
std_Name=${!var}
Alternatively, you could store the names in an array. Then you wouldn't have to do any parsing.
student.properties
student_names=("aaaa" "bbbb" "cccc" "dddd" "eeee")
student.sh
#!/bin/bash
. /student.properties
for student_name in "${student_names[#]}"; do
...
done
You can use indirect expansion:
std_Name=student_name_$i
echo "${!std_Name}"
the expression ${!var} basically evaluates the variable twice:
first evaluation: student_name_1
second evaluation: foo
Note that this is rarely a good idea and that using an array is almost always preferred.
This question already has answers here:
What is the purpose of the : (colon) GNU Bash builtin?
(12 answers)
Closed 8 years ago.
See: What is the Bash equivalent of Python's pass statement
What is this ":" colon usage called? For example:
if [[ -n $STRING ]]; then
#printf "[INFO]:STRING: if -n string: STRING:$STRING \n"
:
else
printf "[INFO]:Nothing in the the string\n"
fi
To what that is, run help : in the shell. It gives:
$ help :
:: :
Null command.
No effect; the command does nothing.
Exit Status:
Always succeeds.
Very useful in one-liner infinite loops, for example:
while :; do date; sleep 1; done
Again, you could write the same thing with true instead of :, but this is shorter.
Interestingly:
$ help true
true: true
Return a successful result.
Exit Status:
Always succeeds.
According to this, the difference is that : is "Null command",
while true is "Returns a successful result".
Another difference is that true is usually a real binary:
$ which true
/usr/bin/true
On the other hand, which : gives nothing. (Which makes sense, being a "null command".)
Anyway, #Andy is right, this is duplicate of this other post, which explains it much better.