Here’s a piece of Linux/UNIX shell scripting code that will do a recursive FTP refresh of a website for you:

lftp <<~/Tmp/log_file.tmp 2>>~/Tmp/log_file.tmp

open ${HOSTNAME}

user ${USER} ${PSSWD}

mirror -R -vvv “${REP_SRC}” “${REP_DEST}”

EndFTP

When my normal FTP scripting approach left me with a broken WordPress installation and an invalid ticket in the project’s TRAC system that I had to close, I turned to looking for a more robust way of achieving the website updates and that’s what led me to seek out the options available for FTP transfers that explicitly involve directory recursion. The key pieces in the code above are the use of lftp in place of ftp, my more usual tool for the job, and the invocation of the mirror command that comes with lftp. The -R switch ensures that file transfer is from local to remote (vice versa is the default) and -vvv turns on maximum verbosity, a very useful thing when you find that it takes longer than more usual means. It’s all much slicker than writing your own script to do the back-work of ploughing through the directory structure and ensuring that the recursive transfers take place. Saying that, it is possible to have a one line variant of the above but the way that I have set things up might be more familiar to users of ftp.

The primary job done by the touch command in UNIX or Linux is to update the time stamps on files. However, it also has another function: creating an empty text file where you are "touching" a file that doesn’t exist. This has its uses, particularly when you want to reduce the amount of pointing and clicking that you need to do or you want to generate a series of empty files in a shell script. Whatever you do with it is up to you.

I recently was having a play with using a shell script to do some folder creation to help me set up a system for testing and I started to hit ownership issues that caused some shell script errors. At the time, I didn’t realise that there is a test that you can perform for ownership. The "-o" in the code below kicks in the test condition and avoids the error in question.

if [[ -o $dirname ]]
then
    cd test
    for i in 1 2 3 4 5 6 7 8 9 10
    do
        if [[ -d study$i ]]
        then
            :
        else
            mkdir study$i
        fi
    done
    ls
    cd ~
fi

Previously, I shared a way to test for directory (-d operator) and file (-f operator) existence that follows the above coding convention. However, there are a plethora of others and I have made a list of them here:

It’s all useful stuff when you want to rid the command line output of errors in an above board sort of way. These are the kinds of things that often make life easier…