Shell script -- check whether the file exists

Write a script to check whether a file exists. If so, output its details. If not, the system prompts that the output file does not exist. Before providing this script, let's take a look at the following commands: file upload.zip.

1. # ll-h upload.zip

-Rw-r -- 1 root 3.3 M 06-28 23:21 upload.zip

2. # file upload.zip

Upload.zip: Zip archive data, at least v1.0 to extract

3. # ls-I upload.zip

1427041 upload.zip

4. # df-h upload.zip

File System capacity used available % mount point

/Dev/hda3 9.5G 5.7G 3.4G 64%/

The following script combines these commands to display the details of a file.

#! /Bin/bash

# This script gives information about a file.

FILENAME = "$1"

Echo "Properties for $ FILENAME :"

If [-f $ FILENAME]; then

Echo "Size is $ (ls-lh $ FILENAME | awk '{print $5 }')"

Echo "Type is $ (file $ FILENAME | cut-d": "-f2 -)"

Echo "Inode number is $ (ls-I $ FILENAME | cut-d" "-f1 -)"

Echo "$ (df-h $ FILENAME | grep-v File System | awk '{print" On ", $1 ",\

Which is mounted as the ", $6," partition ."}')"

Else

Echo "File does not exist ."

Fi

Remember to grant the script executable permission !!!!

Chomd u + x wenjian. sh

The script execution result is as follows:

#/Jiaoben/wenjian. sh upload.zip

Properties for upload.zip:

Size is 3.3 M

Type is Zip archive data, at least v1.0 to extract

Inode number is 1427041

On/dev/hda3, which is mounted as the/partition.

This is much easier than checking the file information by one command.

If you are not familiar with the cut command, you can refer to the following instructions:

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The cut command can extract text columns from a text file or text stream.

Command usage:

Cut-B list [-n] [file...]

Cut-c list [file...]

Cut-f list [-d delim] [-s] [file...]

The preceding-B,-c, and-f indicate byte, character, and field, that is, byte, character, and field, respectively );

List indicates the range of-B,-c, and-f operations.-n often indicates a specific number;

File indicates the name of the text file to be operated;

Delim full English: delimiter) indicates the delimiter, which is a TAB by default;

-S indicates that rows without delimiters are not included. This helps remove comments and titles)

In the preceding three methods, bytes-B),-c), or field-f are extracted from the specified range ).

Range representation:

M

Only entry M

M-

From entry M to end of the row

M-N

From item M to item N (including N)

-N

From the beginning of a row to N (including N)

-

All items from the beginning to the end of a row

Example:

# Cat example

Test2

This is test1

# Cut-c1-6 example # the first 6 characters starting with print

Test2

This I

-C m-n indicates that the MB to n characters of each line are displayed. For example:

--------- File -----------

Wokao 84 25000

--------- File -----------

# Cut-c 1-5, 10-25 file

Wokao 25000

-F m-n indicates to display column m to column n (separated by tab ). For example:

--------- File -----------

Wokao 84 25000

--------- File -----------

# Cut-f 1, 3 file

Wokao 25000

We often encounter some specific fields in the file that need to retrieve the field, for example,/etc/password is separated. You can use the cut command. For example,

We want to save the system account name to a specific file:

Cut-d ":"-f 1/etc/passwd>/tmp/users

-D is used to define the delimiter. The default Delimiter is the tab key.-f indicates the field to be obtained.

For example:

Separated by |

Cut-d' | '-f2 1. test> 2. test

Separated:

Cut-d': '-f2 1. test> 2. test

You can use single or double quotation marks here.