UNIX commands — Working with files

To create a new file, you can either save it from within a text editor (or other program), or you can use the touch command:

[server]$ touch filename

This creates an empty file named filename in the current working directory.

To move a file to another place:

[server]$ mv /old/location/filename /new/location/filename

Note that you can also use relative paths:

[server]$ mv filename ../directory/filename

To copy a file to another place:

[server]$ cp /existing/location/filename /new/location/filename

mv is also used to rename a file to something else:

[server]$ mv oldfilename newfilename

mv can also be used to move a file to a new directory while renaming it:

[server]$ mv oldfilename ../directory/newfilename 

You can also rename a file while using the cp command:

[server]$ cp /existing/location/filename /new/location/newfilename 

To delete a file:

[server]$ rm filename 

You can use wildcards to delete multiple files with similar names. To delete all files beginning with "pic" (eg, pic01.jpg, pic02.jpg, etc):

[server]$ rm pic*

The wildcard can appear anywhere in the string. To delete all .jpg files:

[server]$ rm *.jpg

Be careful when using wildcards as you can inadvertently delete files this way. As a safeguard, you can use the -i flag; you will then be asked to confirm all deletions. Type y or n as prompted to confirm whether or not you wish to delete the each file:

[server]$ rm -i *.jpg
rm: remove 'example1.jpg'? y
rm: remove 'example2.jpg'? y

To permanently remove a directory and all its contents, use the -rf flags:

[server]$ rm -rf directoryname

To locate all of the files in a directory tree that contain some pattern in their name:

[server]$ find directory -name <regexp> -print
list
of
results

Note that this command uses a regular expression (<regexp>) to describe the filename. You can also type in the exact filename.

For example, to find all files ending with htm in the current directory and any subdirectories:

[server]$ find . -name *.htm -print

Note that searches containing wildcards ("*", ".","?") should be bounded by quotes so that the shell does not try to interpret them as regular expressions:

[server]$ find . -name "*.htm" -print

Further, -print is the default on most Unix/Linux systems so it can be omitted in most instances:

[server]$ find . -name "*.htm"

The find command is extremely powerful. Another handy use is to delete all of the empty subfolders in a particular tree. For example:

[server]$ find . -depth -type d -empty -exec rmdir {} ';'

Just make sure to include the -empty flag within the above command.

This command searches in the current directory and all sub directories. All files that contain the string will have their path printed to standard output:

[server]$ find . -exec grep "some_string" '{}' \; -print

To find all the files that have been modified in the last 7 days and output them to a file:

[server]$ find . -mtime -7 > mod.txt