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apps/nshlib/nsh_fsutils.c: As noted by David S. Alessio, 'cat' should not output any additional newline at the end of the cat'ed file content. This was done to assure that the NSH prompt was presented on a new line. However, that is not the correct behavior of 'cat' per the IEEE std: "The standard output shall contain the sequence of bytes read from the input files. Nothing else shall be written to the standard output." Reference: https://pubs.opengroup.org/onlinepubs/009695399/utilities/cat.html

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This commit changes the function nsh_catfile() which underlies the 'cat' command and well as other NSH commands.  Although this is the correct behavior for 'cat' it may not be the correct behavor for other commands implemented via nsh_catfile().  That remains to be determined.
This commit is contained in:
Gregory Nutt 2019-07-29 20:44:57 -06:00
parent b3c705d70c
commit 49e08ca3a9
1 changed files with 5 additions and 12 deletions
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17
nshlib/nsh_fsutils.c
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@ -76,7 +76,6 @@ int nsh_catfile(FAR struct nsh_vtbl_s *vtbl, FAR const char *cmd,
FAR const char *filepath)
{
FAR char *buffer;
char last = 0;
int fd;
int ret = OK;
@ -130,7 +129,6 @@ int nsh_catfile(FAR struct nsh_vtbl_s *vtbl, FAR const char *cmd,
{
int nbyteswritten = 0;
last = buffer[nbytesread - 1];
while (nbyteswritten < nbytesread)
{
ssize_t n = nsh_write(vtbl, buffer + nbyteswritten, nbytesread - nbyteswritten);
@ -168,18 +166,13 @@ int nsh_catfile(FAR struct nsh_vtbl_s *vtbl, FAR const char *cmd,
}
}
/* Make sure that the following NSH prompt appears on a new line. If the
* file ends in a newline, then this will print an extra blank line
* before the prompt, but that is preferable to the case where there is
* no newline and the NSH prompt appears on the same line as the cat'ed
* file.
/* NOTE that the following NSH prompt may appear on the same line as file
* content. The IEEE Std requires that "The standard output shall
* contain the sequence of bytes read from the input files. Nothing else
* shall be written to the standard output." Reference:
* https://pubs.opengroup.org/onlinepubs/009695399/utilities/cat.html.
*/
if (ret == OK && last != '\n')
{
nsh_output(vtbl, "\n");
}
/* Close the input file and return the result */
(void)close(fd);