how to add additional command-line usage scenarios to script?

Question

how can one make this script work with both input usage scenarios below?

#1 ./script.sh #2 ./script.sh input.file 

contents of script.sh

for i in *.mp4; do ffmpeg -i "$i" "${i%.*}.mp4

scenario #1 is the only one working right now because the file contents above specifically allow one to run script.sh within a directory where all .mp4 files will be targeted.

is it possible to also target an individual file rather than the whole directory, however still keep the other usage scenario #1 available at all times to use.

UPDATE: I do not see how this is related the the question he is commenting about.

Answer 1

Just use the argument as the path. You can use a simple trick: /path/to/dir/./ is the same as /path/to/dir/ since ./ means 'the current directory. So for this simple case, you could just do:

#!/bin/bash for i in "$1"./*.mp4; do ffmpeg -i "$i" "${i%.*}.mp4"; done 

And then run the script either like this:

cd /path/to/mp4; /path/to/script.sh 

Or like this (the final slash is essential):

/path/to/script.sh /path/to/mp4/ 

---

The general way of doing this is something like this:

#!/bin/bash ## Assign the 1st argument to the variable "target" target=$1 ## If $target has no value (if $1 was empty), set it to "." target=${target:="."} for i in "$target"/*.mp4; do ffmpeg -i "$i" "${i%.*}.mp4"; done 

The variable isn't actually needed, you can just do:

#!/bin/sh for i in ${1-.}/*.mp4; do echo ffmpeg -i "$i" "${i%.*}.mp4"; done 

Or:

#!/bin/sh if [ -z "$1" ]; then target="." else target="$1" fi for i in "$target"/*.mp4; do ffmpeg -i "$i" "${i%.*}.mp4"; done