bash script to automate wget tar cd using word designators and word modifiers

Question

How can I automate the following with a bash shell script using word designators and word modifiers or something similar? ``` root@server:/tmp# wget -q http://download.zeromq.org/zeromq-2.2.0.tar.gz root@server:/tmp# tar -xzf !$:t tar -xzf zeromq-2.2.0.tar.gz root@server:/tmp# cd !$:r:r cd zeromq-2.2.0 root@server:/tmp/zeromq-2.2.0# ``` When I try something like the below I get errors because word designators and word modifiers don't appear to work the same way in bash scripts as they do in a shell: Bash Shell Script Example 1: ``` #!/usr/bin/env bash wget -q http://download.zeromq.org/zeromq-2.2.0.tar.gz && tar -xzf !$:t && cd !$:r:r root@server:/tmp# ./install.sh tar (child): Cannot connect to !$: resolve failed gzip: stdin: unexpected end of file tar: Child returned status 128 tar: Error is not recoverable: exiting now ``` Bash Shell Script Example 2: ``` #!/usr/bin/env bash wget -q http://download.zeromq.org/zeromq-2.2.0.tar.gz tar -xzf !$:t cd !$:r:r root@server:/tmp# ./install.s…

Accepted Answer

History substitution works at the command line. In a script, you can use parameter expansion.

```
#!/usr/bin/env bash
url=http://download.zeromq.org/zeromq-2.2.0.tar.gz
wget -q "$url"
tarfile=${url##*/}        # strip off the part before the last slash
tar -xzf "$tarfile"
dir=${tarfile%.tar.gz}    # strip off ".tar.gz"
cd "$dir"
```

bash script to automate wget tar cd using word designators and word modifiers

Solution

Problem