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### 2.3 Shell Commands

If you need to execute occasional shell commands during your debugging session, there is no need to leave or suspend gdb; you can just use the `shell` command.

`shell` command-string
`!`command-string
  Invoke a standard shell to execute command-string. Note that no space is needed between `!` and command-string. On GNU and Unix systems, the environment variable `SHELL`, if it exists, determines which shell to run. Otherwise gdb uses the default shell (`/bin/sh` on GNU and Unix systems, `cmd.exe` on MS-Windows, `COMMAND.COM` on MS-DOS, etc.).

The utility `make` is often needed in development environments. You do not have to use the `shell` command for this purpose in gdb:

`make` make-args
  Execute the `make` program with the specified arguments. This is equivalent to ``shell make make-args`'.

`pipe [`command`] |` shell_command
`| [`command`] |` shell_command
`pipe -d` delim command delim shell_command
`| -d` delim command delim shell_command
  Executes command and sends its output to shell_command. Note that no space is needed around `|`. If no command is provided, the last command executed is repeated.

  In case the command contains a `|`, the option `-d` delim can be used to specify an alternate delimiter string delim that separates the command from the shell_command.

  Example:

                (gdb) p var
                $1 = {
                  black = 144,
                  red = 233,
                  green = 377,
                  blue = 610,
                  white = 987
                }
                (gdb) pipe p var|wc
                      7      19      80
                (gdb) |p var|wc -l
                7
                (gdb) p /x var
                $4 = {
                  black = 0x90,
                  red = 0xe9,
                  green = 0x179,
                  blue = 0x262,
                  white = 0x3db
                }
                (gdb) ||grep red
                  red => 0xe9,
                (gdb) | -d ! echo this contains a | char\n ! sed -e 's/|/PIPE/'
                this contains a PIPE char
                (gdb) | -d xxx echo this contains a | char!\n xxx sed -e 's/|/PIPE/'
                this contains a PIPE char!
                (gdb)

The convenience variables `$_shell_exitcode` and `$_shell_exitsignal` can be used to examine the exit status of the last shell command launched by `shell`, `make`, `pipe` and `|`. See Convenience Variables.