Pipe the output of basename to string substitution

Question

I need the basename of a file that is given as an argument to a bash script. The basename should be stripped of its file extension. Let's assume $1 = "/somefolder/andanotherfolder/myfile.txt", the desired output would be "myfile".

The current attempt creates an intermediate variable that I would like to avoid:

BASE=$(basename "$1")
NOEXT="${BASE%.*}"

My attempt to make this a one-liner would be piping the output of basename. However, I do not know how to pipe stdout to a string substitution.

EDIT: this needs to work for multiple file extensions with possibly differing lengths, hence the string substitution attempt as given above.

Thanks. For the first answer by @oguzismail: How do I replace the variable name "BASE" once it is a one liner? — stee, Jul 01 '20 at 09:39
@KamilCuk That only works for one specific file ending (txt in this case). — stee, Jul 01 '20 at 09:40
@Cyrus I did. Unless I'm missing something this is not possible with basename alone. — stee, Jul 01 '20 at 09:43
Have a look at this answer https://stackoverflow.com/a/965072/11934850 of Petesh to a similar question. — Sascha Doerdelmann, Jul 01 '20 at 09:47
@KamilCuk : This suggestion implies that we already know that the extension is `.txt`. From the code the OP provided, in particular the calculation of `NOEXT`, I would assume that the extension can be anything. — user1934428, Jul 01 '20 at 09:59
@SaschaDoerdelmann The answer you mention explains how to do it in two steps, which is the current approach that I have described in the question. — stee, Jul 01 '20 at 10:09

Orsiris de Jong · Accepted Answer · 2020-07-02T12:45:49.957

5

Why not Zoidberg ? Ehhmm.. I meant why not remove the ext before going for basename ?

basename "${1%.*}"

Unless of course you have directory paths with dots, then you'll have to use basename before and remove the extension later:

echo $(basename "$1") | awk 'BEGIN { FS = "." }; { print $1 }'

The awk solution will remove anything after the first dot from the filename.

There's a regular expression based solution which uses sed to remove only the extension after last dot if it exists:

echo $(basename "$1") | sed 's/\(.*\)\..*/\1/'

This could even be improved if you're sure that you've got alphanumeric extensions of 3-4 characters (eg: mp3, mpeg, jpg, txt, json...)

echo $(basename "$1") | sed 's/\(.*\)\.[[:alnum:]]\{3\}$/\1/'

edited Jul 02 '20 at 12:45

answered Jul 01 '20 at 10:27

Orsiris de Jong

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I really like the first option for the sake of simplicity and readability. Paths including dots could be an issue though. – stee Jul 01 '20 at 10:41
Actually, I just tried this with a path containing foldernames using dots and it worked out. – stee Jul 01 '20 at 10:44
Indeed it will work even with paths that contains dots, but only if your filename has contains a dot too. if $1= '/some.dir/myfile' it would cut at the first trailing dot it finds. The second version is just more safe to use, even if it's uglier ;) But bash isn't the most beautiful script lang anyway IMO ;) – Orsiris de Jong Jul 01 '20 at 10:50
You're right. On the flipside of the coin: The awk solution does not work properly if the filename itself contains a dot before the file ending. – stee Jul 01 '20 at 11:37
So after some more thought it seems like the cleanest, yet ugly solution may be this: `echo $(basename "$1") | rev | cut -d"." -f 2- | rev` It will get the basename and remove everything after the last `.` of the basename. – stee Jul 01 '20 at 11:39
That's a lot of uglyness indeed. I added a sed based solution which uses regular expressions to restrict to file extensions. – Orsiris de Jong Jul 02 '20 at 12:47

Léa Gris · Answer 2 · 2020-07-01T10:48:03.427

3

How about this?

NEXT="$(basename -- "${1%.*}")"

Testing:

set -- '/somefolder/andanotherfolder/myfile.txt'
NEXT="$(basename -- "${1%.*}")"
echo "$NEXT"

myfile

Alternatively:

set -- "${1%.*}"; NEXT="${1##*/}"

edited Jul 01 '20 at 10:48

answered Jul 01 '20 at 10:28

Léa Gris

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score 2 · Answer 3 · answered Jul 01 '20 at 10:23

2

NOEXT="${1##*/}"; NOEXT="${NOEXT%.*}"

answered Jul 01 '20 at 10:23

alecxs

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avoid intermediate variable ;) – alecxs Jul 01 '20 at 10:26
1

Ha! sneaky one ;p – stee Jul 01 '20 at 10:38

James Brown · Answer 4 · 2020-07-01T10:13:38.030

1

How about:

$ [[ $var =~ [^/]*$ ]] && echo ${BASH_REMATCH%.*}
myfile

edited Jul 01 '20 at 10:13

answered Jul 01 '20 at 09:43

James Brown

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Pipe the output of basename to string substitution

4 Answers4