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pa4080
Asked: 2017-10-07 02:46:50 +0800 CST

Is there any way to create backup copy of a file, without type its name twice? [duplicate]

  • 772

Often when I'm editing some system file first I create a backup copy. For example:

sudo cp /etc/ssh/sshd_config /etc/ssh/sshd_config.bak

Is there any simple 'shortcut' such as:

sudo cp /etc/ssh/sshd_config %s.bak

?

A workaround that I found is to use sed in this way:

sudo sed '' /etc/ssh/sshd_config -i.bak
command-line

2 Answers

  1. Best Answer

    You could use brace expansion like this:

    cp example_file{,.bak}
    • 33

  2. 1. What you asked for

    You can create a small shellscript file bupper:

    I have a directory ~/bin, where I keep such help files.

    #!/bin/bash

if [ $# -eq 1 ]
then
 cp -pvi "$1" "${1}.bak"
else
 echo "Info:  $0 copies to a backup file"
 echo "Usage: $0 <file to be backed up with .bak extension>"
fi

    Make it executable,

    chmod ugo+x bupper

    When in ~/bin, it will be in PATH and you can run it like any executable program anywhere (where you have write permissions).

    Example:

    $ bupper hello.txt 
'hello.txt' -> 'hello.txt.bak'
$ bupper hello.txt 
cp: overwrite 'hello.txt.bak'? n
$ bupper hello.txt 
cp: overwrite 'hello.txt.bak'? y
'hello.txt' -> 'hello.txt.bak'

    2. Alternative - let the editor do the job automatically

    Some editors have an option to create a backup copy of the file before you save a new version. This backup has often a tilde as the last character (tilde is the extension, but there is no dot before it).

    Gedit, the standard editor in Ubuntu is one of them.

    enter image description here

    After setting gedit to save such a backup copy:

    gedit hello.txt

    And check afterwards

    $ ls hello.txt*
hello.txt  hello.txt~  hello.txt.bak

    Now hello.txt~ has been added to hello.txt and the backup created by bupper.

    This works with nano too, with the option -B

    nano -B hello.txt

    so you can do it with a command line editor for 'sudo' tasks :-)

    • 4