Shell Programming and Scripting

pline itself is variable

pline is a variable.

Edit: heh, posting clash battle of the giants (-:

Hi,

If I tried to print out $pline outside the awk command, its empty.

//racbern

Hi again,

The script doesnt work if the pline is a blank line.

How can I add a validation inside the awk command to check if pline is blank line to get the line above the blank line instead?

Thanks a lot again,

//racbern

Code:

awk '/EXECUTE/ { start = 1; continue }
/END/ { start = 0; continue }
start && /[Ee]rror|failed|warning/ { print pline; print }
/./ { pline = $0 }' file

The dot matches lines which contain a character. If you want a non-blank character, change the dot to something like [^ ]

The awk script handles the whole file in one go; by the time your shell regains control over execution, "pline" will no longer be meaningful.

Generally, to get both output on standard output and a value into a variable from a single child process is extremely tricky. My suggestion would be to make the awk script print its output in such a form that you can then unambiguously identify which lines are "plines" when reading the output back into the shell script. Something like

Code:

awk '... print "pline " pline; print "output " $0 ' ... |
while read type line; do
  case $type in
    pline) echo this is a pline: "$line";;
    output) echo this is real output for that pline: "$line";;
  esac
done

Do you see what I'm getting at? Make awk print a single extra identifier at the start of every line, so your shell script can read that and discard it, but then handle the different types of lines differently depending on what the value of the discarded identifier was.