將命令結果賦值給一個變數
阿新 • • 發佈:2019-02-02
#!/bin/bash a=23 # Simple case echo $a b=$a echo $b echo # Now, getting a little bit fancier (command substitution). a=`echo Hello!` # Assigns result of 'echo' command to 'a' ... echo $a # Note that including an exclamation mark (!) within a #+ command substitution construct will not work from the command-line, #+ since this triggers the Bash "history mechanism." # Inside a script, however, the history functions are disabled. a=`ls -l /home` # Assigns result of 'ls -l' command to 'a' echo $a # Unquoted, however, it removes tabs and newlines. echo echo "$a" # The quoted variable preserves whitespace. # (See the chapter on "Quoting.") exit 0
結果:
23
23
Hello!
total 8 drwxrwxrwx 15 root root 4096 2012-10-27 10:47 code drwxr-xr-x 4 user user 4096 2012-10-24 12:58 user
total 8
drwxrwxrwx 15 root root 4096 2012-10-27 10:47 code
drwxr-xr-x 4 user user 4096 2012-10-24 12:58 user