InputList="Item1,Item2,Item3,....,ItemN"
Desired output:
NewList1="Item1"
NewList2="Item2;Item3;....;ItemN"
Note that the separator of the original input list is a , (comma) whereas that of the new lists is a ; (semicolon).
Please suggest a suitable Bash script. Thanks.
With bash and its Parameter Expansion:
InputArray="Item1,Item2,Item3,....,ItemN"
List1="${InputArray%%,*}"
List2="${InputArray#*,}"
List2="${List2//,/;}"
echo "$List1"
echo "$List2"
Output:
Item1
Item2;Item3;....;ItemN
You can use arrays and IFS.
InputList='Item1,Item2,Item3,....,ItemN'
IFS=, InputArray=($InputList)
NewList1="${InputArray[0]}"
NewList2="$(IFS=\;; printf '%s' "${InputArray[*]:1}")"
Related
I have two strings saved in a bash variable delimited by :. I want to get extract the second string, prepend that with THIS_VAR= and append it to a file named saved.txt
For example if myVar="abc:pqr", THIS_VAR=pqr should be appended to saved.txt.
This is what I have so far,
myVar="abc:pqr"
echo $myVar | cut -d ':' -f 2 >> saved.txt
How do I prepend THIS_VAR=?
printf 'THIS_VAR=%q\n' "${myVar#*:}"
See Shell Parameter Expansion and run help printf.
The more general solution in addition to #konsolebox's answer is piping into a compound statement, where you can perform arbitrary operations:
echo This is in the middle | {
echo This is first
cat
echo This is last
}
I am trying to split the string by double back slashes in bash and somehow it's not working.
My string is as follow:
abc\\xyz
My Code:
my_str='abc\\xyz'
IFS='\\' read -r -a arr <<< "$my_str"
echo "${#arr[#]}"
I am expecting that the output would be '2' as the length of the array would be 2.
However, I get 3 as a result and when I try to print the array values, I only get 'abc', and the second index remains empty. It seems like something is wrong with my code but I am unable to identify it.
Can anyone please help to resolve the issue?
If there are no spaces in your string you could use bash pattern substitutions to replace pairs of backslashes by a space and assign the result to an indexed array:
$ my_str='abc\\xyz\uvw\\rst\\\012\\\\345'
$ declare -a arr=( ${my_str//\\\\/ } )
$ echo "${#arr[#]}"
5
$ printf '%s\n' "${arr[#]}"
abc
xyz\uvw
rst
\012
345
Perhaps you could try to replace the backslashes on the string fist as showcased in this previous question. However, this would be inefficient for very large strings.
A slightly different take -
$: my_str='abc\\123\\ghi\\\012\\jkl\\foo bar\\\\xyz'
$: IFS='|' read -r -a arr <<< "${my_str//\\\\/\|}"
$: printf "[%s]\n" "${arr[#]}"
[abc]
[123]
[ghi]
[\012]
[jkl]
[foo bar]
[]
[xyz]
I have a variable MyVar with values stored in it. For example:
MyVar="123, 234, 345, 456"
Each entry in the variable is separated by a coma as in the example above.
I want to be able to pick the first and last entry from this variable, i.e 123 and 456 respectively.
Any idea how I can achieve this from the command prompt terminal ?
Thanks!
Using bash substring removal:
$ echo ${MyVar##*,}
456
$ echo ${MyVar%%,*}
123
Also:
$ echo ${MyVar/,*,/,}
123, 456
More for example here:
https://tldp.org/LDP/abs/html/parameter-substitution.html
Edit: Above kind of expects the substrings to be separated by commas only. See comments where #costaparas gloriously demonstrates a case with , .
Try using sed:
MyVar="123, 234, 345, 456"
first=$(echo "$MyVar" | sed 's/,.*//')
last=$(echo "$MyVar" | sed 's/.*, //')
echo $first $last
Explanation:
To obtain the first string, we replace everything after & including
the first comma with nothing (empty string).
To obtain the last string, we replace everything before & including the last comma with nothing (empty string).
Using bash array:
IFS=', ' arr=($MyVar)
echo ${arr[0]} ${arr[-1]}
Where ${arr[0]} and ${arr[-1]} are your first and last respective values. Negative index requires bash 4.2 or later.
You could try following also with latest BASH version, by sending variable values into an array and then retrieve first and last element, keeping all either values in it saved in case you need them later in program etc.
IFS=', ' read -r -a array <<< "$MyVar"
echo "${array[0]}"
123
echo "${array[-1]}"
456
Awk alternative:
awk -F "(, )" '{ print $1" - "$NF }' <<< $MyVar
Set the field separator to command and a space. Print the first field and the last field (NF) with " - " in between.
I have tried few options but that not working on my case. My requirement is..
Suppose I have a parameter in a file and wanted to capture the details as below and run a shell script(ksh).
PARAMETR=aname1:7,aname2:5
The parameter contains 2 values delimited by a comma and each value separated by a colon.
So, wanted to process it as if the string matched as aname1 then print both in different variable $v1=aname1 and $v2=7. The same applies to the other value too if string searched as aname2 then $v1=aname2 and $v2=5.
Thank you in advance.
That will do what you're asking for
#!/bin/ksh
typeset -A valueArray
PARAMETR=aname1:7,aname2:5
paramArray=(${PARAMETR//,/ })
for ((i=0;i<=${#paramArray[#]};i++)); do
valueArray[${paramArray[$i]%:*}]=${paramArray[$i]#*:}
done
for j in ${!valueArray[#]}; do
print "$j = ${valueArray[$j]}"
done
Hope it can help
First split the line in two sets and than process each set.
echo "${PARAMETR}" | tr "," "\n" | while IFS=: read -r v1 v2; do
echo "v1=$v1 and v2=$v2"
done
Result:
v1=aname1 and v2=7
v1=aname2 and v2=5
I run a script with the param -A AA/BB . To get an array with AA and BB, i can do this.
INPUT_PARAM=(${AIRLINE_OPTION//-A / }) #get rid of the '-A ' in the begining
LIST=(${AIRLINES_PARAM//\// }) # split by '/'
Can we achieve this in a single line?
Thanks in advance.
One way
IFS=/ read -r -a LIST <<< "${AIRLINE_OPTION//-A /}"
This places the output from the parameter substitution ${AIRLINE_OPTION//-A /} into a "here-string" and uses the bash read built-in to parse this into an array. Splitting by / is achieved by setting the value of IFS to / for the read command.
LIST=( $(IFS=/; for x in ${AIRLINE_OPTION#-A }; do printf "$x "; done) )
This is a portable solution, but if your read supports -a and you don't mind portability then you should go for #1_CR's solution.
With awk, for example, you can create an array and store it in LIST variable:
$ LIST=($(awk -F"[\/ ]" '{print $2,$3}' <<< "-A AA/BB"))
Result:
$ echo ${LIST[0]}
AA
$ echo ${LIST[1]}
BB
Explanation
-F"[\/ ]" defines two possible field separators: a space or a slash /.
'{print $2$3}' prints the 2nd and 3rd fields based on those separators.