Have a file1 with vname and vport

Vname vport
xyc    3:4:7
sdf    5:5:5
sft    5:5:5
sfg    3:4:7
szd    1:2:3

Get the unique port

vport 1:2:3

and separate and assign each of them to a variable like a=1, b=2, c=3

  • 1
    It's not clear to me what are you trying to achieve. Can you give more detailed example?
    – mrc02_kr
    Nov 14, 2019 at 8:50
  • Do I understand you correctly that you are looking for a line starting with szd and then want to read the corresponding vport value into the three variables?
    – AdminBee
    Nov 14, 2019 at 8:51
  • When you say "get unique port", does that mean no a can be equal to a b or c? Or a/b/c should be unique regardless of each others?
    – SYN
    Nov 14, 2019 at 9:15

2 Answers 2


Does this answer your question?


# IFS is a special enviroment variable. The character in it will be used
# by 'read' (which is a bash builtin command).
# In this case we need space and colon as separators
IFS=' :'

# Looping over lines in the file, fo each line read name, a, b, and c.

# "sed 1d" command deletes first line to skip over header ("Vname vport")
sed 1d file1 | while read name a b c ; do

    # If it was an empty line, skip and loop to next line
    [ "$name" ] || continue

    # output the variables for demonstration
    echo "name: $name"
    echo "a = $a"
    echo "b = $b"
    echo "c = $c"

    # extra line to separate output of next line

  • I am curious: since you alread specified IFS, why don't you just use while read name a b c; do <...> done?
    – AdminBee
    Nov 14, 2019 at 10:23
  • No real reason, just me doing it overly complex :) Edited. Thanks.
    – Hkoof
    Nov 14, 2019 at 14:33

I assume that you want to identify that vport combination which only occurs once in the file, and want to split that into the three variables a, b and c. In this case, you could make use of associative arrays:

The following should work:


declare -A counts   # declare `counts` as associative container

# Read the file line-wise
while read vname vport
    if [[ "$vname" == "Vname" ]]; then continue; fi # skip header

    # if current 'vport' value not yet encountered, add it to the array
    # with count=1, otherwise increment the value
    if [[ -z "${counts[$vport]}" ]]
        let counts[$vport]=${counts[$vport]}+1
done < file.txt

# Identify which one only occurs once: iterate over all "keys" and
# check which "value" is "1"
for vp in "${!counts[@]}"
    # If such a key was found, split it at the ':' and read the parts
    # into individual variables
    if [[ "${counts[$vp]}" == "1" ]]
        read a b c <<< "$vp"

# Output the variables if a unique port specification was found
if (( found == 1 ))
    echo "Unique port found: a=$a, b=$b, c=$c"
    echo "No unique port found!"

Note that this assumes there is only one such unique port (which seems reasonable to guess from your example).

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