awk and windows paths backslash escape character

Question

Here I found a nice way to extract basename from path with awk:

awk 'BEGIN{ var="Z:\201708021541\file name with spaces.123"; n=split(var,a,/\//); print a[n]}'

but for backslashes it does not work as the characters seem to become escaped, e.g. the output of the above looks:

Z:�708021541
            ile name with spaces.123

Now, is there any way to get around in awk? The paths are listed in a file and I cannot (do not want) to preprocess all the files to escape \, so I wonder is there a way to tell awk "do not escape"?

Do you need the basename in `awk` or do you use `awk` because `basename` does not understand Windows paths? — Kusalananda, Mar 07 '18 at 22:37

Kusalananda · Answer 1 · 2018-03-07T22:55:59.923

Assuming that you are trying to find the filename portion of a Windows pathname containing backslashes...

pathname='Z:\201708021541\file name with spaces.123'
filename=$(basename "${pathname//\\//}")

printf '%s\n' "$filename"

This will print

file name with spaces.123

if run in bash.

The parameter substitution ${pathname//\\//} replaces all backslashes with forward slashes in the value of $pathname, which means that the standard basename utility can work on it. The basename utility does not care that the path starts with Z: (it believes that this is the name of a directory).

Alternatively (shorter, and more portable):

pathname='Z:\201708021541\file name with spaces.123'
filename=${pathname##*\\}

printf '%s\n' "$filename"

Here, ${pathname##*\\} will remove everything up to the last backslash in $pathname. This parameter substitution is standard, whereas the one used in the first variation will only work in certain shells.

Using awk:

printf '%s\n' "$pathname" | awk '{ sub(".*\\\\", "", $0); print }'

The four backslashes are two backslashes escaped once each, because reasons.

Using sed:

printf '%s\n' "$pathname" | sed 's/.*\\//'

Both the awk and sed solutions work exactly the same way. They substitute everything up to (and including) the last backslash with an empty string.

awk and windows paths backslash escape character

1 Answers1