Shell Script-1

.: Denotes any character

*: Matches the previous character, A * indicates: 0 or more A

+: Matches the preceding character to represent 1 or more preceding characters

?: matches the preceding character to represent 0 or more preceding characters

#！ /bin/bash #!/bin/sh Opening

Comments:

: <<! Eof!

Write code here

! Eof!

Can be the SH 1.sh to execute the script, or the right to chmod a+x 1.sh and then./1.sh

Sh-x: Can be used to debug scripts

Date +%y: Year (M-month, D-Day, H-hour, M-minute, S-second, s = number of seconds from January 1, 1970 to present, W week, W is now the first week)

Date-d " -1day" + "%F%T": Indicates this time of yesterday

Export can declare global variables, which can take effect in child shells

$: script itself

$#: The script uses several parameters

$n: Represents the nth parameter

If

Format: note [] There are spaces on both sides

if Conditions

Then

echo "true";

elif [condition]; then

echo "false";

Else

echo "Error";

fi

>:GT, <:it, >=:ge, <=:le, ==:eq,!=:ne

-a means that &&,-o represents | |

If determine file, directory properties
[-F file] Determines if it is a normal file, and there is
[-D file] Determines if it is a directory and exists
[-E file] to determine whether files or directories exist
[-R File] to determine if the document is readable
[-W file] Determines whether the file is writable
[-X file] Determines whether the file is executable

exec >/tmp/$d. Log 2>&1: You can append the actual error to the/tmp/*.log

Generally written on top of the script, you can output all the logs executed by the script

when a variable is defined n=1 do not add spaces on either side of the equals sign

June 15, 2015

By:champly

Shell Script-1