What does cut return if the specified field does not exist

cuttext processing

I have a string:

6.40.4

and a second one:

6.40

I am using var=$(echo $versionfull | cut -d'.' -f3) to get the third digit from the first string in bash. What does this command return for the second one? It looks empty but either [ -z $var ] or [ $var == "" ] does not work. I want to give it a value of 0 in case of a second string.

Best Answer

You could use var=$(echo "${versionfull}.0" | cut -d'.' -f3).

In the first case, versionfull will contain 6.40.4.0, ignoring the padding and returning 4 as needed. In the second case, the .0 will be padded and returned.

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How to use cut command to get the first and last elements of a row

On your version of SunOS nawk(or for that matter awk) should be able to do the trick

 nawk -F';' 'BEGIN{OFS=";"}{print($1,$2,$3,$(NF-1),$(NF))}' file.txt

AWK – Joining Multiple Columns from Different Files

$ cat tst.awk
BEGIN { FS=OFS="\t" }
{ datasets[$1]; fnames[FILENAME]; vals[$1,FILENAME] = $2 }
END {
    printf "%s", "dataset"
    for (fname in fnames) {
        printf "%s%s", OFS, fname
    }
    print ""
    for (dataset in datasets) {
        printf "%s", dataset
        for (fname in fnames) {
            printf "%s%s", OFS, vals[dataset,fname]
        }
        print ""
    }
}

$ tail -n +1 file?
==> file1 <==
a       1
b       2
c       3

==> file2 <==
a       2
c       3

$ awk -f tst.awk file1 file2
dataset file1   file2
a       1       2
b       2
c       3       3

Add as many files to the list as you like.

Best Answer

Related Solutions

How to use cut command to get the first and last elements of a row

AWK – Joining Multiple Columns from Different Files

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