Question:

with input csv file

sid,storeNo,latitude,longitude 2,1,-28.03720000,153.42921670 9

I wish to output only the lines with one column, in this example it's line 3. how can this be done in bash shell script?

<strong>Using awk</strong>

The following awk would be usfull

$ awk -F, 'NF==1' inputFile 9

<strong>What it does?</strong>

<ul><li>

-F, sets the field separator as ,

</li> <li>

NF==1 matches lines with NF, number of fields as 1. No action is provided hence default action, printing the entire record is taken. it is similar to NF==1{print $0}

</li> <li>

inputFile input csv file to the awk script

</li> </ul>

<strong>Using grep</strong>

The same function can also be done using grep

$ grep -v ',' inputFile 9 <ul><li>

-v option prints lines that do not match the pattern

</li> <li>

, along with -v greps matches lines that do not contain , field separator

</li> </ul>

<strong>Using sed</strong>

$ sed -n '/^[^,]*$/p' inputFile 9

<strong>what it does?</strong>

<ul><li>

-n suppresses normal printing of pattern space

</li> <li>

'/^[^,]*$/ selects lines that match the pattern, lines without any ,

<ul><li>

^ anchors the regex at the start of the string

</li> <li>

[^,]* matches anything other than ,

</li> <li>

$ anchors string at the end of string

</li> </ul></li> <li>

p action p makes sed to print the current pattern space, that is pattern space matching the input

</li> </ul>

try this bash script

#!/bin/bash while read -r line do IFS="," set -- $line case ${#} in 1) echo $line;; *) continue;; esac done < file