I'm using a script that uses curl to obtain specific array values from a configuration. I'd like to place the output into columns separating values (values are unknown to script). Here's my code:
# get overlay networks and their details
get_overlay=`curl -H "X-Person-Token: $auth_token" -H "X-Person-Email: $auth_email" -k "$api_host/api/v1/networks"`
# array of overlay names with uuid
overlay_name=`echo $get_overlay | jq '.[] | .name'`
overlay_uuid=`echo $get_overlay | jq '.[] | .uuid'`
echo ""
echo -e "Overlay UUID\n$oname $ouuid" | column -t
exit 0
Here's the ouput:
Overlay UUID
"TESTOVERLAY"
"Auto_API_Overlay"
"ANOTHEROVERLAYTEST" "ea178905-6ab0-4154-ab05-412dc4b39151"
"e5be9dbe-b0fc-4e30-aaf5-ac4bdcd863a7"
"850ebf6b-3651-4cf1-aae1-5a6c03fad61b"
What I was expecting was:
Overlay UUID
"TESTOVERLAY" "ea178905-6ab0-4154-ab05-412dc4b39151"
"Auto_API_Overlay" "e5be9dbe-b0fc-4e30-aaf5-ac4bdcd863a7"
"ANOTHEROVERLAYTEST" "850ebf6b-3651-4cf1-aae1-5a6c03fad61b"
I'm an absolute beginner at this, any insight is very much appreciated.
Thanks!
I would suggest using paste to combine your two variables line by line:
paste <(printf 'Overlay\n%s\n' "$name") <(printf 'UUID\n%s\n' "$uuid") | column -t
Two process substitutions are used to pass the contents of each variable along with their titles.
Related
Basically I want to automate this task where I have some namespaces in Kubernetes I need to delete and others that I want to leave alone. These namespaces contain the word nginx. So I was thinking in order to do that I could get the output of get namespace using some regex and store those namespaces in an array, then iterate through that array deleting them one by one.
array=($(kubectl get ns | jq -r 'keys[]'))
declare -p array
for n in {array};
do
kubectl delete $n
done
I tried doing something like this but this is very basic and doesn't even have the regex. But I just left it here as an example to show what I'm trying to achieve. Any help is appreciated and thanks in advance.
kubectl get ns doesn't output JSON unless you add -o json. This:
array=($(kubectl get ns | jq -r 'keys[]'))
Should result in an error like:
parse error: Invalid numeric literal at line 1, column 5
kubectl get ns -o json emits a JSON response that contains a list of Namespace resources in the items key. You need to get the metadata.name attribute from each item, so:
kubectl get ns -o json | jq -r '.items[].metadata.name'
You only want namespaces that contain the word "nginx". We could filter the above list with grep, or we could add that condition to our jq expression:
kubectl get ns -o json | jq -r '.items[]|select(.metadata.name|test("nginx"))|.metadata.name'
This will output your desired namespaces. At this point, there's no reason to store this in array and use a for loop; you can just pipe the output to xargs:
kubectl get ns -o json |
jq -r '.items[]|select(.metadata.name|test("nginx"))|.metadata.name' |
xargs kubectl delete ns
kubectl get ns
output
NAME STATUS AGE
default Active 75d
kube-public Active 75d
kube-system Active 75d
oci-service-operator-system Active 31d
olm Active 31d
command
kubectl get ns --no-headers | awk '{if ($1 ~ "de") print $1}'
Output
default
kube-node-lease
this will give you a list of namespaces
array=$(kubectl get ns --no-headers | awk '{if ($1 ~ "de") print $1}')
Testing
bash-4.2$ array=$(kubectl get ns --no-headers | awk '{if ($1 ~ "de") print $1}')
bash-4.2$ echo $array
default kube-node-lease
bash-4.2$ for n in $array; do echo $n; done
default
kube-node-lease
bash-4.2$
Problem:
Writing a bash script, i'm trying to import a list of products that are inside a csv file into an array:
#!/bin/bash
PRODUCTS=(`csvprintf -f "/home/test/data/input.csv" -x | grep "col2" | sed 's/<col2>//g' | sed 's/<\/col2>//g' | sed -n '1!p' | sed '$ d' | sed 's/ //g'`)
echo ${PRODUCTS[#]}
In the interactive shell, the result/output looks perfect as following:
burger
special fries
juice - 300ml
When i use exactly the same commands in bash script, even debugging with bash -x script.sh, in the part of echo ${PRODUCTS[#]}, the result of array is all files names located at /home/test/data/ and:
burger
special
fries
juice
-
300ml
The array is taking directory list AND messed up newlines. This don't happen in interactive shell (single command line).
Anyone know how to fix that?
Looking at the docs for csvprintf, you're converting the csv into XML and then parsing it with regular expressions. This is generally a very bad idea.
You might want to install csvkit then you can do
csvcut -c prod input.csv | sed 1d
Or you could use a language that comes with a CSV parser module. For example, ruby
ruby -rcsv -e 'CSV.read("input.csv", :headers=>true).each {|row| puts row["prod"]}'
Whichever method you use, read the results into a bash array with this construct
mapfile -t products < <(command to extract the product data)
Then, to print the array elements:
for prod in "${products[#]}"; do echo "$prod"; done
# or
printf "%s\n" "${products[#]}"
The quotes around the array expansion are critical. If missing, you'll see one word per line.
Tip: don't use ALLCAPS variable names in the shell: leave those for the shell. One day you'll write PATH=something and then wonder why your script is broken.
I have tried everything I can think of to cut this into separate elements for my array but I am struggling..
Here is what I am trying to do..
(This command just rips out the IP addresses on the first element returned )
$ IFS=$"\n"
$ aaa=( $(netstat -nr | grep -v '^0.0.0.0' | grep -v 'eth' | grep "UGH" | sed 's/ .*//') )
$ echo "${#aaa[#]}"
1
$ echo "${aaa[0]}"
4.4.4.4
5.5.5.5
This shows more than one value when I am looking for the array to separate 4.4.4.4 into ${aaa[0]} and 5.5.5.5 into ${aaa[1]}
I have tried:
IFS="\n"
IFS=$"\n"
IFS=" "
Very confused as I have been working with arrays a lot recently and have never ran into this particular issue.
Can someone tell me what I am doing wrong?
There is a very good example on how to use IFS + read -a to split a string into an array on this other stackoverflow page
How does splitting string to array by 'read' with IFS word separator in bash generated extra space element?
netstat is deprecated, replaced by ss, so I'm not sure how to reproduce your exact problem
I am trying to use xmllint to search an xml file and store the values I need into an array. Here is what I am doing:
#!/bin/sh
function getProfilePaths {
unset profilePaths
unset profilePathsArr
profilePaths=$(echo 'cat //profiles/profile/#path' | xmllint --shell file.xml | grep '=' | grep -v ">" | cut -f 2 -d "=" | tr -d \")
profilePathsArr+=( $(echo $profilePaths))
return 0
}
In another function I have:
function useProfilePaths {
getProfilePaths
for i in ${profilePathsArr[#]}; do
echo $i
done
return 0
}
useProfilePaths
The behavior of the function changes whether I do the commands manually on the command line VS calling them from different function as part of a wrapper script. When I can my function from a wrapper script, the items in the array are 1, compared to when I do it from the command line, it's 2:
$ echo ${#profilePathsArr[#]}
2
The content of profilePaths looks like this when echoed:
$ echo ${profilePaths}
/Profile/Path/1 /Profile/Path/2
I am not sure what the separator is for an xmllint call.
When I call my function from my wrapper script, the content of the first iteration of the for loop looks like this:
for i in ${profilePathsArr[#]}; do
echo $i
done
the first echo looks like:
/Profile/Path/1
/Profile/Path/2
... and the second echo is empty.
Can anyone help me debug this issue? If I could find out what is the separator used by xmllint, maybe I could parse the items correctly in the array.
FYI, I have already tried the following approach, with the same result:
profilePaths=($(echo 'cat //profiles/profile/#path' | xmllint --shell file.xml | grep '=' | grep -v ">" | cut -f 2 -d "=" | tr -d \"))
Instead of using the --shell switch and many pipes, you should use the proper --xpath switch.
But as far of I know, when you have multiple values, there's no simple way to split the different nodes.
So a solution is to iterate like this :
profilePaths=(
$(
for i in {1..100}; do
xmllint --xpath "//profiles[$i]/profile/#path" file.xml || break
done
)
)
or use xmlstarlet:
profilePaths=( $(xmlstarlet sel -t -v "//profiles/profile/#path" file.xml) )
it display output with newlines by default
The problem you're having is related to data encapsulation; specifically, variables defined in a function are local, so you can't access them outside that function unless you define them otherwise.
Depending on the implementation of sh you're using, you may be able get around this by using eval on your variable definition or with a modifier like global for mksh and declare -g for zsh and bash. I know that mksh's implementation definitely works.
Thank you for providing feedback on how I can resolve this problem. After investigating more, I was able to make this work by changing the way I was iterating the content of my 'profilePaths' variable to insert its values into the 'profilePathsArr' array:
# Retrieve the profile paths from file.xml and assign to 'profilePaths'
profilePaths=$(echo 'cat //profiles/profile/#path' | xmllint --shell file.xml | grep '=' | grep -v ">" | cut -f 2 -d "=" | tr -d \")
# Insert them into the array 'profilePathsArr'
IFS=$'\n' read -rd '' -a profilePathsArr <<<"$profilePaths"
For some reason, with all the different function calls from my master script and calls to other scripts, it seemed like the separators were lost along the way. I am unable to find the root cause, but I know that by using "\n" as the IFS and a while loop, it worked like a charm.
If anybody wishes to add more comments on this, you are more than welcome.
For a larger project that's not relevant, I need to collect system stats from the local system or a remote system. Since I'm collecting the same stats either way, I'm preventing code duplication by storing the stats-collecting commands in a Bash associative array.
declare -A stats_cmds
# Actually contains many more key:value pairs, similar style
stats_cmds=([total_ram]="$(free -m | awk '/^Mem:/{print $2}')")
I can collect local system stats like this:
get_local_system_stats()
{
# Collect stats about local system
complex_data_structure_that_doesnt_matter=${stats_cmds[total_ram]}
# Many more similar calls here
}
A precondition of my script is that ~/.ssh/config is setup such that ssh $SSH_HOSTNAME works without any user input. I would like something like this:
get_remote_system_stats()
{
# Collect stats about remote system
complex_data_structure_that_doesnt_matter=`ssh $SSH_HOSTNAME ${stats_cmds[total_ram]}`
}
I've tried every combination of single quotes, double quotes, backticks and such that I can imagine. Some combinations result in the stats command getting executed too early (bash: 7986: command not found), others cause syntax errors, others return null (single quotes around the stats command) but none store the proper result in my data structure.
How can I evaluate a command, stored in an associative array, on a remote system via SSH and store the result in a data structure in my local script?
Make sure that the commands you store in your array don't get expanded when you assign your array!
Also note that the complex-looking quoting style is necessary when nesting single quotes. See this SO post for an explanation.
stats_cmds=([total_ram]='free -m | awk '"'"'/^Mem:/{print $2}'"'"'')
And then just launch your ssh as:
sh "$ssh_hostname" "${stats_cmds[total_ram]}"
(yeah, I lowercased your variable name because uppercase variable names in Bash are really sick). Then:
get_local_system_stats() {
# Collect stats about local system
complex_data_structure_that_doesnt_matter=$( ${stats_cmds[total_ram]} )
# Many more similar calls here
}
and
get_remote_system_stats() {
# Collect stats about remote system
complex_data_structure_that_doesnt_matter=$(ssh "$ssh_hostname" "${stats_cmds[total_ram]}")
}
First, I'm going to suggest an approach that makes minimal changes to your existing implementation. Then, I'm going to demonstrate something closer to best practices.
Smallest Modification
Given your existing code:
declare -A remote_stats_cmds
remote_stats_cmds=([total_ram]='free -m | awk '"'"'/^Mem:/{print $2}'"'"''
[used_ram]='free -m | awk '"'"'/^Mem:/{print $3}'"'"''
[free_ram]='free -m | awk '"'"'/^Mem:/{print $4}'"'"''
[cpus]='nproc'
[one_min_load]='uptime | awk -F'"'"'[a-z]:'"'"' '"'"'{print $2}'"'"' | awk -F "," '"'"'{print $1}'"'"' | tr -d " "'
[five_min_load]='uptime | awk -F'"'"'[a-z]:'"'"' '"'"'{print $2}'"'"' | awk -F "," '"'"'{print $2}'"'"' | tr -d " "'
[fifteen_min_load]='uptime | awk -F'"'"'[a-z]:'"'"' '"'"'{print $2}'"'"' | awk -F "," '"'"'{print $3}'"'"' | tr -d " "'
[iowait]='cat /proc/stat | awk '"'"'NR==1 {print $6}'"'"''
[steal_time]='cat /proc/stat | awk '"'"'NR==1 {print $9}'"'"'')
...one can evaluate these locally as follows:
result=$(eval "${remote_stat_cmds[iowait]}")
echo "$result" # demonstrate value retrieved
...or remotely as follows:
result=$(ssh "$hostname" bash <<<"${remote_stat_cmds[iowait]}")
echo "$result" # demonstrate value retrieved
No separate form is required.
The Right Thing
Now, let's talk about an entirely different way to do this:
# no awful nested quoting by hand!
collect_total_ram() { free -m | awk '/^Mem:/ {print $2}'; }
collect_used_ram() { free -m | awk '/^Mem:/ {print $3}'; }
collect_cpus() { nproc; }
...and then, to evaluate locally:
result=$(collect_cpus)
...or, to evaluate remotely:
result=$(ssh "$hostname" bash <<<"$(declare -f collect_cpus); collect_cpus")
...or, to iterate through defined functions with the collect_ prefix and do both of these things:
declare -A local_results
declare -A remote_results
while IFS= read -r funcname; do
local_results["${funcname#collect_}"]=$("$funcname")
remote_results["${funcname#collect_}"]=$(ssh "$hostname" bash <<<"$(declare -f "$funcname"); $funcname")
done < <(compgen -A function collect_)
...or, to collect all the items into a single remote array in one pass, avoiding extra SSH round-trips and not eval'ing or otherwise taking security risks with results received from the remote system:
remote_cmd=""
while IFS= read -r funcname; do
remote_cmd+="$(declare -f "$funcname"); printf '%s\0' \"$funcname\" \"\$(\"$funcname\")\";"
done < <(compgen -A function collect_)
declare -A remote_results=( )
while IFS= read -r -d '' funcname && IFS= read -r -d '' result; do
remote_results["${funcname#collect_}"]=$result
done < <(ssh "$hostname" bash <<<"$remote_cmd")