> $ cat test1 > trap 'echo "$BASH_COMMAND"' DEBUG > echo hello > $ cat test2 > trap '(echo "$BASH_COMMAND")' DEBUG > echo hey > bash
And the content of the test files was really: $ cat test1 trap 'echo "$BASH_COMMAND"' DEBUG echo hey $ cat test2 trap '(echo "$BASH_COMMAND")' DEBUG echo hey Sorry again. On 04/11/2021, Emanuele Torre <torreemanue...@gmail.com> wrote: >> And noticed that $BASH_COMMAND always expanded to: >> >> read -p "[...:...] $BASH_COMMAND? >> >> where the ...:... is the expanded value of $BASH_SOURCE:$LINENO. > > Err, sorry about that. I misremembered. > > It is actually expanding to > > read -p "[$BASH_SOURCE:$LINENO] $BASH_COMMAND" > > as it would normally do when used outside of a trap. > > The rest of the issue is still valid. > > > On 04/11/2021, Emanuele Torre <torreemanue...@gmail.com> wrote: >> Configuration Information [Automatically generated, do not change]: >> Machine: x86_64 >> OS: linux-gnu >> Compiler: gcc >> Compilation CFLAGS: -march=x86-64 -mtune=generic -O2 -pipe -fno-plt >> -DDEFAULT_PATH_VALUE='/usr/local/sbin:/usr/local/bin:/usr/bin' >> -DSTANDARD_UTILS_PATH='/usr/bin' -DSYS_BASHRC='/etc/bash.bashrc' >> -DSYS_BASH_LOGOUT='/etc/bash.bash_logout' >> -DNON_INTERACTIVE_LOGIN_SHELLS >> uname output: Linux t420 5.10.75-1-lts #1 SMP Wed, 20 Oct 2021 >> 11:02:09 +0000 x86_64 GNU/Linux >> Machine Type: x86_64-pc-linux-gnu >> >> Bash Version: 5.1 >> Patch Level: 8 >> Release Status: release >> >> Description: >> BASH_COMMAND does not expand to the expected value when used in a >> subshell inside a trap. >> >> I tried using the following DEBUG trap that i got from >> http://mywiki.wooledge.org/BashGuide/Practices in bash-5.1: >> >> trap '(read -p "[$BASH_SOURCE:$LINENO] $BASH_COMMAND?")' DEBUG >> >> And noticed that $BASH_COMMAND always expanded to: >> >> read -p "[...:...] $BASH_COMMAND? >> >> where the ...:... is the expanded value of $BASH_SOURCE:$LINENO. >> >> Then I tried to use the same trap in bash-4.4 and it worked as >> expected. >> >> Repeat-By: >> >> $ cat test1 >> trap 'echo "$BASH_COMMAND"' DEBUG >> echo hello >> $ cat test2 >> trap '(echo "$BASH_COMMAND")' DEBUG >> echo hey >> bash >> >> $ ./bash test1 # bash-4.4 >> echo hey >> hey >> $ ./bash test2 # bash-4.4 >> echo hey >> hey >> $ bash test1 # bash-5.1 >> echo hey >> hey >> $ bash test2 # bash-5.1 >> echo "$BASH_COMMAND" >> hey >> >> $ ./bash --version | head -1 >> GNU bash, version 4.4.0(3)-release (x86_64-unknown-linux-gnu) >> $ bash --version | head -1 >> GNU bash, version 5.1.8(1)-release (x86_64-pc-linux-gnu) >> >
