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STDBUF(1) User Commands STDBUF(1) NAME stdbuf - Run COMMAND, with modified buffering operations for its standard streams. SYNOPSIS stdbuf OPTION... COMMAND DESCRIPTION Run COMMAND, with modified buffering operations for its standard streams. Mandatory arguments to long options are mandatory for short options too. -i, --input=MODE adjust standard input stream buffering -o, --output=MODE adjust standard output stream buffering -e, --error=MODE adjust standard error stream buffering --help display this help and exit --version output version information and exit If MODE is 'L' the corresponding stream will be line buffered. This option is invalid with standard input. If MODE is '0' the corresponding stream will be unbuffered. Otherwise MODE is a number which may be followed by one of the following: KB 1000, K 1024, MB 1000*1000, M 1024*1024, and so on for G,T,P,E,Z,Y,R,Q. Binary prefixes can be used, too: KiB=K, MiB=M, and so on. In this case the corresponding stream will be fully buffered with the buffer size set to MODE bytes. NOTE: If COMMAND adjusts the buffering of its standard streams ('tee' does for example) then that will override corresponding changes by 'stdbuf'. Also some filters (like 'dd' and 'cat' etc.) don't use streams for I/O, and are thus unaffected by 'stdbuf' settings. Exit status: 125 if the stdbuf command itself fails 126 if COMMAND is found but cannot be invoked 127 if COMMAND cannot be found - the exit status of COMMAND otherwise EXAMPLES tail -f access.log | stdbuf -oL cut -d ' ' -f1 | uniq This will immediately display unique entries from access.log BUGS On GLIBC platforms, specifying a buffer size, i.e., using fully buffered mode will result in undefined operation. AUTHOR Written by Padraig Brady. REPORTING BUGS Report bugs to: bug-coreutils@gnu.org GNU coreutils home page: <https://www.gnu.org/software/coreutils/> General help using GNU software: <https://www.gnu.org/gethelp/> Report any translation bugs to <https://translationproject.org/team/> COPYRIGHT Copyright (C) 2025 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>. This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. SEE ALSO Full documentation <https://www.gnu.org/software/coreutils/stdbuf> or available locally via: info '(coreutils) stdbuf invocation' GNU coreutils 9.9 November 2025 STDBUF(1)
NAME | SYNOPSIS | DESCRIPTION | EXAMPLES | BUGS | AUTHOR | REPORTING BUGS | COPYRIGHT | SEE ALSO
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