This project has objective to build a prompt with shell commands
License: Apache License 2.0
new Topics to Study:
About Me:
🌱 Learning:
📌 Pinned:
echo only print arguments but not parse if exist or not variable
expected:
echo $PWD
echo $SHELL
this print must be return values
ok
We need create a some way to store variables local or global for system
Command: set
Command: env
Local variables = only readable in shell level currently
Global variables = readable in shell level currently and in next levels
(based on the PATH variable or using a relative or an absolute path)
What's happend?
When run command exit, command exit return status code 1 and infinite loop break only when status code is equal 1, different of 1 loop didn`t break.
What expected?
When run exit, infinite loop of main must broken loop
When execute exit -1 the main function must to return exit_code to first bash called minishell
./minishell << EOF
exit 1
EOF
echo $? // must be 1
./minishell << EOF
exit a
EOF
echo $? // must be 2
./minishell << EOF
exit -1
EOF
echo $? // must be 255
Commands need return:
Must return: bash: exit: too many arguments
ERROR CODE: 127 or 1 ? Need check
Must return: bash: exit: a: numeric argument required
ERROR CODE: 2
Must return: exit
ERROR CODE: 8
Must return: exit
ERROR CODE: 254
NOTE: Mod of 255 to return 254 just like bash
What happen?
When press CTRL + D the minishell stay locked in infinite loop printing >
What expected?
When press CTRL + d only exit the program cleaning all struct and exit after
Handle environment variables ($ followed by a sequence of characters) which should expand to their values
which are not required by the subject such as \ (backslash) or ; (semicolon)
Handle ctrl-C, ctrl-D and ctrl-\ which should behave like in bash
Important to think: Global Variable create a strong dependency, maybe this can broke future changes in code
Main contains to many functions and commands.
This file main.c can be shorted with group of struct and same object
When start minishell and press enter without command
==1105==
==1105== HEAP SUMMARY:
==1105== in use at exit: 1 bytes in 1 blocks
==1105== total heap usage: 36 allocs, 35 frees, 5,236 bytes allocated
==1105==
==1105== 1 bytes in 1 blocks are definitely lost in loss record 1 of 1
==1105== at 0x4848899: malloc (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==1105== by 0x10B124: ft_strdup (in /app/minishell)
==1105== by 0x109722: read_keyboard (input.c:40)
==1105== by 0x10945B: minishell (main.c:46)
==1105== by 0x109580: main (main.c:73)
==1105==
==1105== LEAK SUMMARY:
==1105== definitely lost: 1 bytes in 1 blocks
==1105== indirectly lost: 0 bytes in 0 blocks
==1105== possibly lost: 0 bytes in 0 blocks
==1105== still reachable: 0 bytes in 0 blocks
==1105== suppressed: 0 bytes in 0 blocks
==1105==
==1105== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)
Handle " (double quote) which should prevent the shell from interpreting the metacharacters in the quoted sequence except for $ (dollar sign).
Ref: https://www.computerhope.com/unix/bash/export.htm
Definition of done:
The shell shall format the output, including the proper use of quoting, so that it is suitable for reinput to the shell
as commands that achieve the same exporting results, except:
1. Read-only variables with values cannot be reset.
2. Variables that were unset at the time they were output need not be reset to the unset state if a value is assigned
to the variable between the time the state was saved and the time at which the saved output is reinput to the
shell.
When no arguments are given, the results are unspecified. If a variable assignment precedes the command name of export
but that variable is not also listed as an operand of export, then that variable shall be set in the current shell exe‐
cution environment after the completion of the export command, but it is unspecified whether that variable is marked
for export.
What's happend?
Execute a wrong command and in valgrind show this message
==1141== 1 errors in context 2 of 2:
==1141== Use of uninitialised value of size 8
==1141== at 0x109665: execute_cmd (commands.c:25)
==1141== by 0x10939D: minishell (main.c:57)
==1141== by 0x10949D: main (main.c:80)
==1141== Uninitialised value was created by a heap allocation
==1141== at 0x4848899: malloc (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==1141== by 0x109434: main (main.c:75)
==1141==
==1141== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 0 from 0)
What's expected?
only show message bash: COMMAND: command not found without leaks
We need compliance with branch main
Handle single quote which should prevent the shell from interpreting the meta characters in the quoted sequence
When execute command, the adapter receive char *arg but must be a list of words.
This can be solved convert this unique sentence of string to a matrix of strings. char *str to char **strgs for example.
Can be a Matrix, Linked list, Array ...
Example of standard commands strtok this command convert string to token
#include <stdio.h>
#include <string.h>
char *strtok_custom(char *str, const char *delim) {
static char *last = NULL;
char *token;
// If str is not NULL, start from the beginning
if (str != NULL)
last = str;
// If last is NULL, there are no more tokens
if (last == NULL)
return NULL;
// Skip leading delimiters
last += strspn(last, delim);
// If last points to the end of the string, there are no more tokens
if (*last == '\0')
return NULL;
// Find the end of the current token
token = last;
last = strpbrk(last, delim);
if (last != NULL) {
// If a delimiter is found, replace it with a null terminator
*last = '\0';
last++;
}
return token;
}
What happen?
segment faultWhat expected?
Implement pipes (| character). The output of each command in the pipeline is connected to the input of the next command via a pipe
Handle $? which should expand to the exit status of the most recently executed foreground pipeline.
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