shell 脚本 - 运行命令列表

Question

for i in `cat foo.txt`
do
    $i
done

And I have a input file "foo.txt", with list of commands.

ls -ltr | tail
ps -ef | tail
mysql -e STATUS | grep "^Uptime"

when I run the shell script, it executes, but splits the commands in each line at spaces ie for first line it executes only "ls", then "-ltr" for which I get command not found error.

How can I run each list as one command?

why am I doing this?

I execute lot of arbitrary shell commands including DB commands. I need to have a error handling as I execute each command(each line from foo.txt), I can't think of what can go wrong, so the idea is put all commands in order and call them in loop and check for error (#?) at each line and stop on error.

Answer 1

Why not just do this?

set -e
. ./foo.txt

set -e causes the shell script to abort if a command exits with a non-zero exit code, and . ./foo.txt . ./foo.txt executes commands from foo.txt in the current shell.

---

but I guess I can't send notification (email).

Sure you can. Just run the script in a subshell, and then respond to the result code:

#!/bin/sh

(
set -e
. ./foo.txt
)

if [ "$?" -ne 0 ]; then
  echo "The world is on fire!" | mail -s 'Doom is upon us' you@youremail.com
fi

Answer 2

Code mentioned.

for i in `cat foo.txt`
do
    $i
done     

Please use https://www.shellcheck.net/

This will result    _ 
    $ shellcheck myscript

Line 1:
for i in `cat foo.txt`
^-- SC2148: Tips depend on target shell and yours is unknown. Add a shebang.
         ^-- SC2013: To read lines rather than words, pipe/redirect to a 'while read'   loop.
         ^-- SC2006: Use $(...) notation instead of legacy backticked `...`.

Did you mean: (apply this, apply all SC2006)
for i in $(cat foo.txt)

$ 

Will try while loop, and for test purpose content of foo.txt mentioned below

cat foo.txt
    ls -l /tmp/test
    ABC
    pwd



 while read -r line; do $line; if [ "$?" -ne 0 ]; then echo "Send email Notification stating  $line Command reported error "; fi; done < foo.txt

 total 0
-rw-r--r--. 1 root root 0 Dec 24 11:41 test.txt
bash: ABC: command not found...
Send email Notification stating  ABC Command reported error
/tmp

In case error reported you can break the loop. http://tldp.org/LDP/Bash-Beginners-Guide/html/sect_09_05.html

while read -r line; do $line; if [ "$?" -ne 0 ]; then echo "Send email Notification  stating  $line Command reported error "; break; fi; done < foo.txt

total 0
-rw-r--r--. 1 root root 0 Dec 24 11:41 test.txt
bash: ABC: command not found...
Send email Notification stating  ABC Command reported error




 while read -r line; do eval $line; if [ "$?" -ne 0 ]; then echo "Send email Notification stating  $line Command reported error "; break; fi; done < foo.txt
total 0
-rw-r--r--. 1 root root 0 Dec 24 11:41 test.txt
   bash: ABC: command not found...
Send email Notification stating  ABC Command reported error