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If you want to read a line and get all the bytes in it, use gets() which reads from stdin. If you have a binary file that is not being correctly interpreted by gets(), then consider using fread(). We can also tell how many lines are available before we’ve reached EOF with feof( ).
The following program illustrates these concepts:
#include “stdio.h”
int main ( ) { char buffer [ BUFSIZ ] ; FILE * infile = fopen ( “file.txt” , “rt” ) ; while ( ! feof ( infile ) ) { puts ( buffer + strlen ( buffer ) , infile ) } return 0 ; } //EOF
int main ( ) { char buffer [ BUFSIZ ] ; FILE * infile = fopen ( “file.txt” , “rt” ) ; while ( ! feof ( infile ) ) { puts ( buffer + strlen ( buffer ) , infile ) } return 0 ; } //EOF
To read a file line by line, we use the gets() function to get input from stdin and then print it out with printf(). In this example, I am reading lines in from my C prompt using the cat command which concatenates files together on stdout so that they can be seen one at
If you have been using the readline function to get input from a user, then this is how you can EOF when reading:
read -u 0 foo # Update with your variable name. This reads up until end-of-file echo $?
exit code of zero means that all data was read successfully and processed by bash. If it is not successful (i.e., exit code !=0), an error message will be printed on stderr describing why it failed. Exit codes are also available as part of the shell’s status word; see test(n). This behavior may differ if stdin has been redirected in some way or another for example through lesspipe() or cmd&=”less”.
EOF when reading a line: g the cat command which concatenates files together on stdout so that they can be seen one at a time. If you have been using the readline function to get input from a user, then this is how you can EOF (end-of-file) when reading:
read -u 0 foo # Update with your variable name. This reads up until end of file echo $?
exit code of zero means all data was successfully processed by bash and not an error message will be printed saying why it failed but if exited out in some way or another for example through lesspipe() or cmd&=”less” exit codes are also available as part of the shell’s status.
Exit Code: Exit Codes Explained (This section is optional) The following is a list that covers common errors, which can occur when reading from a line, using read to get input from the user, and how to identify them based on their corresponding exit codes.
-bash: read: cannot open input: Bad file descriptor (error code is 13) – this error message means that the program was not able to be opened for reading, or there’s an underlying problem with the data you are trying to process. This can also mean there might be a permissions issue in which bash doesn’t have access to it due to your permission level being set too low on certain files. Try running “ls -l” and looking through what permission levels exist for both the directory where you’re executing from as well as any directories above it for common patterns such as 77, 750, etc., then lower them if needed so they match up with other settings on harder-to-access folders like /etc/
-bash: read: cannot open input: Bad file descriptor (error code is 13) – this error message means that the program was not able to be opened for reading, or there’s an underlying problem with the data you are trying to process. This can also mean there might be a permissions issue in which bash doesn’t have access to it due to your permission level being set too low on certain files. Try running “ls -l” and looking through what permission levels exist for both the directory where you’re executing from as well as any directories above it for common patterns such as 77, 750, etc., then lower them if needed so they match up with other settings on harder-to-access folders like /etc/ – The permissions on these files should be 700, and the right to read them should belong to either root or the user.
-bash: read: cannot open input: Bad file descriptor (error code is 13) – this error message means that the program was not able to be opened for reading, or there’s an underlying problem with the data you are trying to process. This can also mean there might be a permissions issue in which bash doesn’t have access to it due to your permission level being set too low on certain files. Try running “ls -l” and looking through what permission levels exist for both the directory where you’re executing from as well as any directories above it for common patterns such as 77, 750, etc., then lower your permission levels appropriately.
-bash: read: cannot open input: Bad file descriptor (error code is 13) – this error message means that the program was not able to be opened for reading, or there’s an underlying problem with the data you are trying to process. This can also mean there might be a permissions issue in which bash doesn’t have access to it due to your permission level being set too low on certain files. Try running “ls -l” and looking through what permissions exist for both the directory where you’re executing from as well as any directories above it for common patterns such as 77, 750, etc., then lower your permission levels accordingly.
On these files should be 700, and the right to read should be set to the owning user. To fix this, run “chmod 700 filename” and then “ls -l”.
-bash: read: cannot open input: Bad file descriptor (error code is 13) – this error message means that the program was not able to be opened for reading, or there’s an underlying problem with the data you are trying to process. This can also mean there might be a permissions issue in which bash doesn’t have access to it due to your permission level being set too low on certain files. Try running “ls -l” and looking through what permissions exist for both the directory where you’re executing from as well as any directories above it for common patterns such as 77, 750, etc., and changing them as necessary. This is a common error when trying to read from certain files like databases, or if you’re using wrong permissions on the file itself – which could be either too permissive (ie: 77) or not permissive enough (ie: 00). This can also happen due to other bugs in your code and should be fixed immediately for any production environment-related scripts that are reading input. If this happens during development then it’s likely just an error message caused by a bug with how bash reads data. The command “read” failed because of the following reasons ~~ The terminal output will show something similar to “bash: read:” indicating the line has been terminated by EOF ~~ When running