Following is the content of the file and i need to print only the ticket numbers which are enclosed in "[]". Curious to know if this can be done using both sed and grep commands.

```
[request://Problem/26727777] SSO Components (UAT)
[request://Problem/25709048] [SERVER-SETUP] Setup 14xMDN, 10xPRN 
[request://Problem/26716590] Logs not populated properly from all servers
[request://Problem/23995808] Prod: Create requestmary

```

Output should be:

```
26727777
25709048
26716590
23995808

```

I tried `sed -e 's/[^0-9]//g' ticket | sed '/^$/d'`, but I'm unable to getthe desired output. It also includes other numeric values in the line, and I need to get only the ticket number:

```
226829515211
226855182
2268555334
226819615
226781310
226853999
226828948216

```