| Index Entry |  Section | 
 
  | 
| P |  |  | 
 | p for FIFO file | 12.5 mknod: Make block or character special files | 
 | pad character | 19.2.3 Output settings | 
 | pad instead of timing for delaying | 19.2.3 Output settings | 
 | padding of numeric fields | 21.1.4 Padding | 
 | paragraphs, reformatting | 4.1 fmt: Reformat paragraph text | 
 | parenb | 19.2.1 Control settings | 
 | parent directories and cp | 11.1 cp: Copy files and directories | 
 | parent directories, creating | 12.3 mkdir: Make directories | 
 | parent directories, creating missing | 11.3 install: Copy files and set attributes | 
 | parent directories, removing | 12.6 rmdir: Remove empty directories | 
 | parentheses for grouping | 16.4 expr: Evaluate expressions | 
 | parity | 19.2.5 Combination settings | 
 | parity errors, marking | 19.2.2 Input settings | 
 | parity, ignoring | 19.2.2 Input settings | 
 | parmrk | 19.2.2 Input settings | 
 | parodd | 19.2.1 Control settings | 
 | parsing date strings | 21.1.6 Options for date | 
 | parts of files, output of | 5. Output of parts of files | 
 | pass8 | 19.2.5 Combination settings | 
 | passwd entry, and su shell | 22.5 su: Run a command with substitute user and group id | 
 | paste | 8.2 paste: Merge lines of files | 
 | Paterson, R. | 1. Introduction | 
 | PATH | 22.2 env: Run a command in a modified environment | 
 | PATH | 22.5 su: Run a command with substitute user and group id | 
 | pathchk | 18.3 pathchk: Check file name portability | 
 | pattern matching | 16.4.1 String expressions | 
 | PC filesystem | 14.1 df: Report filesystem disk space usage | 
 | pcfs | 14.1 df: Report filesystem disk space usage | 
 | pebibyte, definition of | 2.2 Block size | 
 | permission tests | 16.3.2 Access permission tests | 
 | permissions of installed files, setting | 11.3 install: Copy files and set attributes | 
 | permissions, changing access | 13.3 chmod: Change access permissions | 
 | permissions, copying existing | 26.2.2 Copying Existing Permissions | 
 | permissions, for changing file timestamps | 13.4 touch: Change file timestamps | 
 | permissions, output by ls | 10.1.2 What information is listed | 
 | petabyte, definition of | 2.2 Block size | 
 | phone directory order | 7.1 sort: Sort text files | 
 | pieces, splitting a file into | 5.3 split: Split a file into fixed-size pieces | 
 | Pinard, F. | 1. Introduction | 
 | Pinard, F. | 27.8 Authors of getdate | 
 | pipe fitting | 17.1 tee: Redirect output to multiple files | 
 | Plass, Michael F. | 4.1 fmt: Reformat paragraph text | 
 | platform, hardware | 21.2 uname: Print system information | 
 | pm in date strings | 27.3 Time of day items | 
 | portable file names, checking for | 18.3 pathchk: Check file name portability | 
 | portable output format | 14.1 df: Report filesystem disk space usage | 
 | POSIX | 1. Introduction | 
 | POSIX output format | 14.1 df: Report filesystem disk space usage | 
 | POSIXLY_CORRECT | 2. Common options | 
 | POSIXLY_CORRECT | 2.5 Standards conformance | 
 | POSIXLY_CORRECT | 4.2 pr: Paginate or columnate files for printing | 
 | POSIXLY_CORRECT | 6.1 wc: Print byte, word, and line counts | 
 | POSIXLY_CORRECT | 7.1 sort: Sort text files | 
 | POSIXLY_CORRECT | 9.1.4 Warning messages | 
 | POSIXLY_CORRECT, and block size | 2.2 Block size | 
 | pr | 4.2 pr: Paginate or columnate files for printing | 
 | prime factors | 25.1 factor: Print prime factors | 
 | print | 9.1.1 Specifying sets of characters | 
 | print name of current directory | 19.1 pwd: Print working directory | 
 | print system information | 21.2 uname: Print system information | 
 | print terminal file name | 19.4 tty: Print file name of terminal on standard input | 
 | printenv | 19.3 printenv: Print all or some environment variables | 
 | printf | 15.2 printf: Format and print data | 
 | printing all or some environment variables | 19.3 printenv: Print all or some environment variables | 
 | printing color database | 10.4 dircolors: Color setup for ls | 
 | printing current user information | 20.6 who: Print who is currently logged in | 
 | printing current usernames | 20.5 users: Print login names of users currently logged in | 
 | printing groups a user is in | 20.4 groups: Print group names a user is in | 
 | printing real and effective uid and gid | 20.1 id: Print real and effective uid and gid | 
 | printing text | 15.1 echo: Print a line of text | 
 | printing text, commands for | 15. Printing text | 
 | printing the current time | 21.1 date: Print or set system date and time | 
 | printing the effective UID | 20.3 whoami: Print effective user id | 
 | printing the host identifier | 21.4 hostid: Print numeric host identifier. | 
 | printing the hostname | 21.3 hostname: Print or set system name | 
 | printing user's login name | 20.2 logname: Print current login name | 
 | printing, preparing files for | 4.2 pr: Paginate or columnate files for printing | 
 | priority, modifying | 22.3 nice: Run a command with modified scheduling priority | 
 | processes, commands for controlling | 23. Process control | 
 | prompting, and ln | 12.2 ln: Make links between files | 
 | prompting, and mv | 11.4 mv: Move (rename) files | 
 | prompting, and rm | 11.5 rm: Remove files or directories | 
 | prompts, forcing | 11.4 mv: Move (rename) files | 
 | prompts, omitting | 11.4 mv: Move (rename) files | 
 | prterase | 19.2.4 Local settings | 
 | ptx | 7.6 ptx: Produce permuted indexes | 
 | punct | 9.1.1 Specifying sets of characters | 
 | pure numbers in date strings | 27.7 Pure numbers in date strings | 
 | pwd | 19.1 pwd: Print working directory | 
 
  | 
| Q |  |  | 
 | quit | 19.2.6 Special characters | 
 | quoting style | 10.1.7 Formatting the file names | 
 
  | 
| R |  |  | 
 | radix for file offsets | 3.4 od: Write files in octal or other formats | 
 | ranges | 9.1.1 Specifying sets of characters | 
 | raw | 19.2.5 Combination settings | 
 | read errors, ignoring | 11.2 dd: Convert and copy a file | 
 | read from stdin and write to stdout and files | 17.1 tee: Redirect output to multiple files | 
 | read permission | 26.1 Structure of File Permissions | 
 | read permission, symbolic | 26.2.1 Setting Permissions | 
 | read system call, and holes | 11.1 cp: Copy files and directories | 
 | readable file check | 16.3.2 Access permission tests | 
 | real uid and gid, printing | 20.1 id: Print real and effective uid and gid | 
 | recursive directory listing | 10.1.1 Which files are listed | 
 | recursively changing access permissions | 13.3 chmod: Change access permissions | 
 | recursively changing file ownership | 13.1 chown: Change file owner and group | 
 | recursively changing group ownership | 13.2 chgrp: Change group ownership | 
 | recursively copying directories | 11.1 cp: Copy files and directories | 
 | recursively copying directories | 11.1 cp: Copy files and directories | 
 | redirection | 17. Redirection | 
 | reformatting paragraph text | 4.1 fmt: Reformat paragraph text | 
 | regular expression matching | 16.4.1 String expressions | 
 | regular file check | 16.3.1 File type tests | 
 | relations, numeric or string | 16.4.3 Relations for expr | 
 | relative items in date strings | 27.6 Relative items in date strings | 
 | release of kernel | 21.2 uname: Print system information | 
 | remainder | 16.4.2 Numeric expressions | 
 | remote hostname | 20.6 who: Print who is currently logged in | 
 | removing empty directories | 12.6 rmdir: Remove empty directories | 
 | removing files after shredding | 11.6 shred: Remove files more securely | 
 | removing files or directories | 11.5 rm: Remove files or directories | 
 | removing files or directories (via the unlink syscall) | 12.7 unlink: Remove files via the unlink syscall | 
 | removing permissions | 26.2.1 Setting Permissions | 
 | repeated characters | 9.1.1 Specifying sets of characters | 
 | repeated output of a string | 15.3 yes: Print a string until interrupted | 
 | restricted deletion flag | 26.1 Structure of File Permissions | 
 | restricted shell | 22.5 su: Run a command with substitute user and group id | 
 | return, ignoring | 19.2.2 Input settings | 
 | return, translating to newline | 19.2.2 Input settings | 
 | return, translating to newline | 19.2.3 Output settings | 
 | reverse sorting | 7.1 sort: Sort text files | 
 | reverse sorting | 10.1.3 Sorting the output | 
 | reversing files | 3.2 tac: Concatenate and write files in reverse | 
 | rm | 11.5 rm: Remove files or directories | 
 | rmdir | 12.6 rmdir: Remove empty directories | 
 | rn format for nl | 3.3 nl: Number lines and write files | 
 | root as default owner | 11.3 install: Copy files and set attributes | 
 | root directory, running a program in a specified | 22.1 chroot: Run a command with a different root directory | 
 | root, becoming | 22.5 su: Run a command with substitute user and group id | 
 | rows | 19.2.7 Special settings | 
 | rprnt | 19.2.6 Special characters | 
 | RTS/CTS flow control | 19.2.1 Control settings | 
 | running a program in a modified environment | 22.2 env: Run a command in a modified environment | 
 | running a program in a specified root directory | 22.1 chroot: Run a command with a different root directory | 
 | rz format for nl | 3.3 nl: Number lines and write files | 
 
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