While loops in Qedit

How do I do a while loop in Qedit/UX?

There are occasions when you need to do a while loop to repeat multiple edit commands in Qedit, typically the edit operations are not on the same line as the condition or data you want to change or edit.

Recently we had the following request:

I am using Qedit for HPUX. I have a file where I would like to execute the following qedit commands until end of file is reached:

fq 707C(1/4)
lq * - 1
c 5/5 C
lq * + 1

Basically, I am trying to change the line previous to one with 707C in positions 1 to 4 for any occurrence of a line with 707C in positions 1 to 4. Is that possible?

Naturally, I wanted to help the customer get the job done, so here is what I came up with in a file called mytest.

rm qedituse
export lines=$(grep '^707C' file | wc -l)
echo tq file >>qedituse
echo lq [    >>qedituse
x=0
while [ $x -lt $lines ]; do 
echo "fq '707C'(1/4);cq 5/5 'C' *-1;lq *+1"  >>qedituse
x=`expr $x + 1`
done
echo k newfile,yes >> qedituse
echo exit          >> qedituse
qedit -c'use qedituse'

The resulting file had the lines with C in column 5 preceeding the 707C. blinC 707C ack ick bla asdfC 707C hippy hoppy frippy froppy a 707 ha ack C 707C Neo%/home/neil: The process broken down as follows: The following just removes the file qedituse and then stores in a variable called lines the number of lines that start with 707C.

rm qedituse
export lines=$(grep '^707C' file | wc -l)

The next two lines simply text in the file and positions the file pointer at the beginning of the file.

echo tq file >>qedituse
echo lq [    >>qedituse

The next portion, is the while loop that will go thru the file "lines" number of times and issue the desidred qedit commands. Notice that cq 5/5 'C' *-1, means put a C in column 5 of the preceding line.

x=0
while [ $x -lt $lines ]; do 
echo "fq '707C'(1/4);cq 5/5 'C' *-1;lq *+1"  >>qedituse
x=`expr $x + 1`
done

The next two lines keep the file and exit

echo kq newfile,yes >> qedituse
echo exit           >> qedituse

The following is run qedit with the editor commands and actually do the task.

qedit -c'use qedituse'

Given what I learned now I would write things a little more compact and do as follows:

rm qedituse
echo t file;l [ >>qedituse
export lines=$(grep '^707C' file | wc -l)
x=0
while [ $x -lt $lines ]; do 
echo "fq '707C'(1/4);cq 5/5 'C' *-1;lq *+1"  >>qedituse
x=`expr $x + 1`
done
echo k newfile,yes;exit >> qedituse
qedit -c'useq qedituse'

You could also use parms and variables to make this even more powerful by allowing you to specify the string to search for etc.