UNIX for Dummies Questions & Answers

ok heres what happened

when trying to execute this script :

while read file user; do
test -e "$file" || continue
# continue to use your imagination here.
# for example, start populating this with just
echo file $file, user $user"
# to see what's going on
done< pdf-to-user.txt


nothing happens. is the supposed to be an open quote at user ? I was also wondering where does the script know the values for $file and $user ?

I modified it and ended up telling it instead of file to use LINE and all it did was print out the list line by line. for now I want to focus on trying to get the script to echo $filename and $user . the text file is basically space separated and it starts with filename 001 username


Thanks for the help .

Yeah, sorry, the opening quote is missing after the echo.

It reads the values from the file. I guess you can guess what "while" does. "read" reads a line of input into the named variable(s) splitting on whitespace. The redirection down at the end of the loop (after "done") says where to get this input from. Without the redirection it would wait for you to type in this information; you could try that just to get a feel for it. (Press ctrl-D when you think you have typed in enough lines.)

The file format should be unadorned, two fields exactly per line, the first is the file name and the second is the corresponding user name. If you want to factor out the ".pdf" extension then that's possible, but I didn't do it.

The "test" checks for the file in the current directory; if it does not exist, the rest of the loop is skipped for this file and user, and the next iteration of the loop is started.

heres what Ive changed and I cant seem to get echo to show any data,.

#!/bin/bash

while read file user; do
test -e "$file" || continue
# continue to use your imagination here.
# for example, start populating this with just
echo "file $file, user $user"
# to see what's going on
done< pdf-to-user.txt

I run this script and nothing happens.

Create one of the files which it expects to find and you should see, well, something. (I was going to write "sparks will fly" but this is really very pedestrian.)

I currently have a directory with 8 pdfs in it. I also have the script and the user text file in the same directory. should there be anything else ? Im running this on CentOS via BASH if that matters.

but Im not getting any output.

Move the echo up before the test to see what is being read and examined.

AHA .. now were getting somewhere. result is .

file 001, user blue
file 002, user green
file 003, user red
file 004, user brown
file 005, user orange


there are 8 pdf files in the directory however it read that data from the user file.

now if I can get it read the directory and pull the filenames from there I should be good. is there any way we can talk outside of the post ? I have an offer for you.