How can I split a string by a delimiter in Bash, storing elements as variables or array elements?

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#1

How do I split a string on a delimiter in Bash? I have a string stored in a variable:

IN="bla@some.com;john@home.com"

I would like to split the string by the “;” delimiter so that I have:

ADDR1="bla@some.com"
ADDR2="john@home.com"

I don’t necessarily need the ADDR1 and ADDR2 variables. If they are elements of an array, that’s even better.

#2

Hiii Kusha,

You can use the Internal Field Separator (IFS) variable to split a string into an array in Bash. Here’s how you can do it:

# Set the input string
IN="bla@some.com;john@home.com"

# Set the IFS to ;
IFS=';' read -ra ADDR <<< "$IN"

# Iterate over the array elements
for i in "${ADDR[@]}"; do
  # process "$i"
  echo "$i"
done

This will split the string by the “;” delimiter and store the parts in the ADDR array. You can then iterate over the array elements and process them as needed.

#3

Hey Kusha,

You can use parameter expansion to split a string into an array in Bash. Here’s an example:

# Set the input string
IN="bla@some.com;john@home.com"

# Replace ';' with ' ' and store the result in an array
arrIN=(${IN//;/ })

# Access elements of the array
echo ${arrIN[1]}  # Output: john@home.com

This approach replaces all occurrences of ‘;’ in the string with a space, then interprets the space-delimited string as an array. It’s a concise way to split a string into an array in Bash.

#4

Hey Kusha,

The cut command is indeed quite useful for parsing delimited text, especially in scenarios like log file processing. Here’s how you can use cut to split a string based on a delimiter:

# Split the string and extract the first field
echo "bla@some.com;john@home.com" | cut -d ";" -f 1

# Split the string and extract the second field
echo "bla@some.com;john@home.com" | cut -d ";" -f 2

In the first command, cut uses ; as the delimiter (-d ";") and extracts the first field (-f 1), giving you bla@some.com. Similarly, the second command extracts the second field (-f 2), giving you john@home.com.

This approach can be extended to process entire files with rows of delimited text. For example, if you have a log file with entries like 2015-04-27|12345|some action|an attribute|meta data, you can use cut in a loop to extract specific fields for further processing.

# Assuming each line in the log file follows the format 'date|id|action|attribute|metadata'
cat logfile.txt | while IFS='|' read -r date id action attribute metadata; do
    # Process each field as needed
    echo "Date: $date, ID: $id, Action: $action, Attribute: $attribute, Metadata: $metadata"
done

In this example, cut is used with the -d option to specify the delimiter as |, and -f is used to extract specific fields from each line.