bash adding a filename to an alias command [duplicate]

Question

I have an alias to a ffmpeg command to start recording a session like this:

alias sreq='ffmpeg -f x11grab -r 24 -s 1024x768 -i :0.0 -qp 0 -c:v libx264 -preset veryslow'

I can just type sreq filename.mkv to start recording. This is pretty good but I'd like to fix this up a bit.

since I always record in .mkv format, how can I have it so that i can avoid having to type .mkv

how could I rework this alias command or something so that I can just type sreq filename or sreq /path/to/filename

and have it work as expected?

jai_s · Accepted Answer · 2016-02-05 16:41:52Z

3

One way is to use a function instead of the alias - put this in your .bashrc or .bash_profile -

sreq()
{
 ffmpeg -f x11grab -r 24 -s 1024x768 -i :0.0 -qp 0 -c:v libx264  -preset veryslow $1.mkv
}

answered Feb 5, 2016 at 16:41

jai_s

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daisy · Accepted Answer · 2016-02-05 16:39:39Z

1

Why don't you just upgrade the alias to a function,

e.g

function sreq() 
{
   ffmpeg -f x11grab -r 24 -s 1024x768 -i :0.0 -qp 0 -c:v libx264 -preset veryslow "$1".mkv
}

When you type sreq /path/to/filename it would become ffmpeg ..(redacted)... /path/to/filename.mkv

answered Feb 5, 2016 at 16:39

daisy

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wow, bash is pretty nice!
– user1610950
Feb 5, 2016 at 16:57
1

This works with almost any bourne-like shell if you remove the function keyword. The POSIX compliant dash shell doesn't understand the function keyword, ksh understands the function keyword sometimes. Most shells understand f() { commands; }.
– RobertL
Feb 5, 2016 at 17:03

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2 Answers 2