My data set(data.txt) looks like this [imageID,sessionID,height1,height2,x,y,crop]:
1,0c66824bfbba50ee715658c4e1aeacf6fda7e7ff,1296,4234,194,1536,0
2,0c66824bfbba50ee715658c4e1aeacf6fda7e7ff,1296,4234,194,1536,0
3,0c66824bfbba50ee715658c4e1aeacf6fda7e7ff,1296,4234,194,1536,0
4,0c66824bfbba50ee715658c4e1aeacf6fda7e7ff,1296,4234,194,1536,950
These are a set of values which I wish to use. I'm new to shell script :) I read the file line by line like this ,
cat $FILENAME | while read LINE
do
string=($LINE)
# PROCESSING THE STRING
done
Now, in the code above, after getting the string, I wish to do the following :
1. Split the string into comma separated values.
2. Store these variables into arrays like imageID[],sessionID[].
I need to access these values for doing image processing using imagemagick.
However, I'm not able to perform the above steps correctly
set -A doesn't work for me (probably due to older BASH on OSX)
Posting an alternate solution using read -a in case someone needs it:
# init all your individual arrays here
imageId=(); sessionId=();
while IFS=, read -ra arr; do
imageId+=(${arr[0]})
sessionId+=(${arr[1]})
done < input.csv
# Print your arrays
echo "${imageId[#]}"
echo "${sessionId[#]}"
oIFS="$IFS"; IFS=','
set -A str $string
IFS="$oIFS"
echo "${str[0]}";
echo "${str[1]}";
echo "${str[2]}";
you can split and store like this
have a look here for more on Unix arrays.
Related
I'm stucked on a bash script.
I'm having a config.ini files like this :
#Username
username=user
#Userpassword
userpassword=password
And i'm looking in a bash script to extract this information and put it in a associative array. My script looks like :
declare -A array
OIFS=$IFS
IFS='='
grep -vE '^(\s*$|#)' file | while read -r var1 var2
do
array+=([$var1]=$var2)
done
echo ${array[#]}
But the array seems to be empty because the commande echo ${array[#]} gives no output.
Any idea why me script don't work ? Thanks for your help and sorry for my bad english.
Common error - "grep | while" causes the while loop to be executed in a separate shell and the variables inside the loop are not global to your shell. Use a here string instead:
while read -r var1 var2
do
array+=([$var1]=$var2)
done <<< $(grep -vE '^(\s*$|#)' file)
Assuming the file can be trusted (ie the content is regulated and known), the simplest method would be to source the ini file and then directly use the variable names within the script:
. config.ini
You can either use the period (.) as above or the source builtin command
I have a file containing config information and a shell script that reads that file. I want to hand over values to a bash script.
file.txt
varNumber=1.1.1
varName=testThis
varFile=~/myDir/mySubDir/output.zip
myShellScript.sh
FILENAME="~/myDir/mySubDir/output.zip" <- this is what I expect from grep/awk
startNextScript.sh -f $FILENAME
I would like to extract the variables either as an associated array or - if easier - grep for them,
but as I'm not used to writing commands like this in bash I am asking for help!
Using associative array in bash:
#!/bin/bash
declare -A vars
while read -r line ; do
var=${line%%=*} # Remove everything after the first =.
value=${line#*=} # Remove everything before the first =.
vars[$var]=$value
done < file.txt
echo Number: ${vars[varNumber]}
echo Name: ${vars[varName]}
echo File: ${vars[varFile]}
I'm trying to read text from a file and then put this in an array split by spaces. I've been trying to follow examples online but my string still appears to not be being split correctly into the array.
nameList=$(cat "test.txt")
echo $nameList
array=($nameList)
echo $array
echo $array[1]
Which just returns the result
this is a test
this
this[1]
As you can see only the first word is being captured by the variable array.
Any suggestions are much appreciated.
To read just one line, split by spaces:
read -r -a array <test.txt
...or to read until the first NUL in the file or its end:
read -r -d '' -a array <test.txt
To access an element of that array:
echo "${array[1]}"
...or better (reliably functional even in cases where the specification for echo is ambiguous, such as if your word is -n or contains backslash literals):
printf '%s\n' "${array[1]}"
I am able to read file into a regular array with a single statement:
local -a ary
readarray -t ary < $fileName
Not happening is reading a file into assoc. array.
I have control over file creation and so would like to do as simply as possible w/o loops if possible at all.
So file content can be following to be read in as:
keyname=valueInfo
But I am willing to replace = with another string if cuts down on code, especially in a single line code as above.
And ...
So would it be possible to read such a file into an assoc array using something like an until or from - i.e. read into an assoc array until it hits a word, or would I have to do this as part of loop?
This will allow me to keep a lot of similar values in same file, but read into separate arrays.
I looked at mapfile as well, but does same as readarray.
Finally ...
I am creating an options list - to select from - as below:
local -a arr=("${!1}")
select option in ${arr[*]}; do
echo ${option}
break
done
Works fine - however the list shown is not sorted. I would like to have it sorted if possible at all.
Hope it is ok to put all 3 questions into 1 as the questions are similar - all on arrays.
Thank you.
First thing, associative arrays are declared with -A not -a:
local -A ary
And if you want to declare a variable on global scope, use declare outside of a function:
declare -A ary
Or use -g if BASH_VERSION >= 4.2.
If your lines do have keyname=valueInfo, with readarray, you can process it like this:
readarray -t lines < "$fileName"
for line in "${lines[#]}"; do
key=${line%%=*}
value=${line#*=}
ary[$key]=$value ## Or simply ary[${line%%=*}]=${line#*=}
done
Using a while read loop can also be an option:
while IFS= read -r line; do
ary[${line%%=*}]=${line#*=}
done < "$fileName"
Or
while IFS== read -r key value; do
ary[$key]=$value
done < "$fileName"
I'm trying to read the lines of output from a subshell into an array, and I'm not willing to set IFS because it's global. I don't want one part of the script to affect the following parts, because that's poor practice and I refuse to do it. Reverting IFS after the command is not an option because it's too much trouble to keep the reversion in the right place after editing the script. How can I explain to bash that I want each array element to contain an entire line, without having to set any global variables that will destroy future commands?
Here's an example showing the unwanted stickiness of IFS:
lines=($(egrep "^-o" speccmds.cmd))
echo "${#lines[#]} lines without IFS"
IFS=$'\r\n' lines=($(egrep "^-o" speccmds.cmd))
echo "${#lines[#]} lines with IFS"
lines=($(egrep "^-o" speccmds.cmd))
echo "${#lines[#]} lines without IFS?"
The output is:
42 lines without IFS
6 lines with IFS
6 lines without IFS?
This question is probably based on a misconception.
IFS=foo read does not change IFS outside of the read operation itself.
Thus, this would have side effects, and should be avoided:
IFS=
declare -a array
while read -r; do
array+=( "$REPLY" )
done < <(your-subshell-here)
...but this is perfectly side-effect free:
declare -a array
while IFS= read -r; do
array+=( "$REPLY" )
done < <(your-subshell-here)
With bash 4.0 or newer, there's also the option of readarray or mapfile (synonyms for the same operation):
mapfile -t array < <(your-subshell-here)
In examples later added to your answer, you have code along the lines of:
lines=($(egrep "^-o" speccmds.cmd))
The better way to write this is:
mapfile -t lines < <(egrep "^-o" speccmds.cmd)
Are you trying to store the lines of the output in an array, or the words of each line?
lines
mapfile -t arrayname < <(your subshell)
This does not use IFS at all.
words
(your subshell) | while IFS=: read -ra words; do ...
The form var=value command args... puts the var variable into the environment of the command, and does not affect the current shell's environment.