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I want to apply grep on particular column in column command.
myfile.txt
3,ST,ST01,3,3,856
3,ST,ST02,4,9,0234
6,N1,N101,2,3,ST
6,N1,N102,1,60,Comcast
6,N1,N103,1,2,92
My Command:
column -s, -t < myfile.txt | grep -w "ST"
Here I want to only grep the pattern ST in 2nd column. How to do this ?
Expected Result:
3 ST ST01 3 3 856
3 ST ST02 4 9 0234
Without doing some fancy RegEx where you count commas, you're better off using awk for this problem.
awk -F, '$2=="ST"'
-F, parameter specifies the delimiter, which is set to a comma for your data.$2 refers to the second column, which is what you want to match on."ST" is the value you want to match.
-v parameter and pass in variables, but if it's an environment variable it's even easier because you can use ENVIRON["TERM"] for your variable in the awk expression itself.
Get ST in column 2 (-E and {1} can be omitted here):
grep -E '^([^,]*,){1}ST[^,]*' file
Output:
3 ST ST01 3 3 856 3 ST ST02 4 9 0234
Get ST in column 6:
grep -E '^([^,]*,){5}ST[^,]*' file | column -s, -t
Output:
6 N1 N101 2 3 ST
By using awk we can select required column,
column -s, -t < myfile.txt | awk '$2 == "ST"'
If shell variable used,
seg="ST"
column -s, -t < $ST_FILE | awk -v var="$seg" '($2 == var)'