4 ms·

How is it more convenient than `mv foo.bar foo.baz`?

by prashnts 10y ago

sdoering 10y ago
Exactly what I was wondering.
- grenoire 10y ago
  Literally the only part that does anything is: mv $vflag $iflag $1 ${1%\.*}.$ext
  - antognini 10y ago
    Yeah, it doesn't do much. But every so often I find myself needing to change the extension of a bunch of files somewhere and needing to write something like "for f in $(ls *.txt); do ... " and then I have to remember how to strip out the prefix (do I use # or % or ##?), and then I have to try it out on a set of test files to make sure I'm not accidentally deleting them all. I figured I would write something in the Unix philosophy to spare me (and maybe others) the trouble. It does exactly one thing, and it (hopefully) does it well. It was also fun to learn how to write a man page and do unit tests for a shell script.
    - boobsbr 10y ago
      you could just add it as a function to a .bash_profile
      - antognini 10y ago
        Very true! Maybe I'll make a gist with a function that can be copied into a .bash_profile.
rogerbinns 10y ago
Now try with more than one file like this: mv *.bar *.baz This is one place where Windows CMD works: ren *.bar *.baz It can't work on Unix shells because wildcard expansion is done before the program (mv) is invoked.
- AdieuToLogic 10y ago
  While not quite as convenient, it's not that tough in bash: ls *.bar | while read f; do mv $f ${f%.bar}.baz; done
  - boobsbr 10y ago
    also as for f in *.bar; do mv $f ${f%txt}baz; done
  - seanp2k2 10y ago
    This is called brace expansion: http://wiki.bash-hackers.org/syntax/expansion/brace http://wiki.bash-hackers.org/syntax/expansion/brace Very useful stuff. E.g. mv nginx.conf{,.old}
  - rogerbinns 10y ago
    Your version above has at least two bugs I see (will fall over with various forms of white space in the filenames). And it would be nice to have interactivity and verboseness (admittedly just flags to mv). It would also be better to work with plain portable shell, rather than requiring bash, so you'll need to include some basename calls. Also should it stop on the first rename failure, or just keep ploughing on no matter what? Before you know it, you have a script you've debugged and tested.
    - AdieuToLogic 10y ago
      The command I whipped up is, by definition, a one-liner meant for situations where the file movement is known by the person wishing to perform it and done interactively. As to the portability of it, yes this is not portable as the syntax relies on substitution syntax supported by a limited number of Unix shells (bash and ksh spring to mind, others may support it too though). Since the OP specifically mentioned: mv foo.bar foo.baz And you pointed out CMD's 'ren' command, the incantation I put forth seemed apropos. YMMV.
      - rogerbinns 10y ago

How is it more convenient than `mv foo.bar foo.baz`?

sdoering 10y ago

Exactly what I was wondering.

grenoire 10y ago
Literally the only part that does anything is: mv $vflag $iflag $1 ${1%\.*}.$ext
- antognini 10y ago
  Yeah, it doesn't do much. But every so often I find myself needing to change the extension of a bunch of files somewhere and needing to write something like "for f in $(ls *.txt); do ... " and then I have to remember how to strip out the prefix (do I use # or % or ##?), and then I have to try it out on a set of test files to make sure I'm not accidentally deleting them all. I figured I would write something in the Unix philosophy to spare me (and maybe others) the trouble. It does exactly one thing, and it (hopefully) does it well. It was also fun to learn how to write a man page and do unit tests for a shell script.
  - boobsbr 10y ago
    you could just add it as a function to a .bash_profile
    - antognini 10y ago
      Very true! Maybe I'll make a gist with a function that can be copied into a .bash_profile.

rogerbinns 10y ago

Now try with more than one file like this: mv *.bar *.baz This is one place where Windows CMD works: ren *.bar *.baz It can't work on Unix shells because wildcard expansion is done before the program (mv) is invoked.

AdieuToLogic 10y ago
While not quite as convenient, it's not that tough in bash: ls *.bar | while read f; do mv $f ${f%.bar}.baz; done
- boobsbr 10y ago
  also as for f in *.bar; do mv $f ${f%txt}baz; done
- seanp2k2 10y ago
  This is called brace expansion: http://wiki.bash-hackers.org/syntax/expansion/brace http://wiki.bash-hackers.org/syntax/expansion/brace Very useful stuff. E.g. mv nginx.conf{,.old}
- rogerbinns 10y ago
  Your version above has at least two bugs I see (will fall over with various forms of white space in the filenames). And it would be nice to have interactivity and verboseness (admittedly just flags to mv). It would also be better to work with plain portable shell, rather than requiring bash, so you'll need to include some basename calls. Also should it stop on the first rename failure, or just keep ploughing on no matter what? Before you know it, you have a script you've debugged and tested.
  - AdieuToLogic 10y ago
    The command I whipped up is, by definition, a one-liner meant for situations where the file movement is known by the person wishing to perform it and done interactively. As to the portability of it, yes this is not portable as the syntax relies on substitution syntax supported by a limited number of Unix shells (bash and ksh spring to mind, others may support it too though). Since the OP specifically mentioned: mv foo.bar foo.baz And you pointed out CMD's 'ren' command, the incantation I put forth seemed apropos. YMMV.
    - rogerbinns 10y ago