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🗒️ NAME

diff - compare files line by line

🚀 Quick Reference

Use Case	Command	Description
Compare two files	diff file1 file2	📝 Show line-by-line differences
Compare directories recursively	diff -r dir1 dir2	📂 Compare all files in subdirectories
Unified diff (compact)	diff -u file1 file2	📄 Show differences with context (default 3 lines)
Context diff	diff -c file1 file2	📄 Show differences with context in separate sections
Ignore whitespace	diff -w file1 file2	🔇 Ignore all whitespace differences
Side-by-side output	diff -y file1 file2	📊 Show two columns
Brief check (different or same)	diff -q file1 file2	🔍 Report only whether files differ
Ignore case	diff -i file1 file2	🔤 Ignore case differences
Show C function context	diff -p file1 file2	🔧 Show which function each change belongs to
Ed script output	diff -e file1 file2	📜 Generate ed commands to patch

📋 SYNOPSIS

diff [OPTION]... FILES

📝 DESCRIPTION

Compare FILES line by line. Mandatory arguments to long options are mandatory for short options too.

• --normal — 📄 output a normal diff (the default)
• -q, --brief — 🔍 report only when files differ
• -s, --report-identical-files — ✅ report when two files are the same
• -c, -C NUM, --context[=NUM] — 📄 output NUM (default 3) lines of copied context
• -u, -U NUM, --unified[=NUM] — 📄 output NUM (default 3) lines of unified context
• -e, --ed — 📜 output an ed script
• -n, --rcs — 📜 output an RCS format diff
• -y, --side-by-side — 📊 output in two columns
• -W, --width=NUM — 📏 output at most NUM (default 130) print columns
• --left-column — 📊 output only the left column of common lines
• --suppress-common-lines — 🙈 do not output common lines
• -p, --show-c-function — 🔧 show which C function each change is in
• -F, --show-function-line=RE — 🔍 show the most recent line matching RE
• --label LABEL — 🏷️ use LABEL instead of file name and timestamp (can be repeated)
• -t, --expand-tabs — ↔️ expand tabs to spaces in output
• -T, --initial-tab — ↔️ make tabs line up by prepending a tab
• --tabsize=NUM — ↔️ tab stops every NUM (default 8) print columns
• --suppress-blank-empty — 🙈 suppress space or tab before empty output lines
• -l, --paginate — 📄 pass output through 'pr' to paginate it
• -r, --recursive — 📂 recursively compare any subdirectories found
• --no-dereference — 🔗 don't follow symbolic links
• -N, --new-file — 📄 treat absent files as empty
• --unidirectional-new-file — 📄 treat absent first files as empty
• --ignore-file-name-case — 🔤 ignore case when comparing file names
• --no-ignore-file-name-case — 🔤 consider case when comparing file names
• -x, --exclude=PAT — 🚫 exclude files that match PAT
• -X, --exclude-from=FILE — 🚫 exclude files that match any pattern in FILE
• -S, --starting-file=FILE — 📂 start with FILE when comparing directories
• --from-file=FILE1 — 📄 compare FILE1 to all operands; FILE1 can be a directory
• --to-file=FILE2 — 📄 compare all operands to FILE2; FILE2 can be a directory
• -i, --ignore-case — 🔤 ignore case differences in file contents
• -E, --ignore-tab-expansion — ↔️ ignore changes due to tab expansion
• -Z, --ignore-trailing-space — 🔇 ignore white space at line end
• -b, --ignore-space-change — 🔇 ignore changes in the amount of white space
• -w, --ignore-all-space — 🔇 ignore all white space
• -B, --ignore-blank-lines — 🙈 ignore changes where lines are all blank
• -I, --ignore-matching-lines=RE — 🙈 ignore changes where all lines match RE
• -a, --text — 📄 treat all files as text
• --strip-trailing-cr — 🔧 strip trailing carriage return on input
• -D, --ifdef=NAME — 🔧 output merged file with '#ifdef NAME' diffs
• --GTYPE-group-format=GFMT — 🔧 format GTYPE input groups with GFMT
• --line-format=LFMT — 🔧 format all input lines with LFMT
• --LTYPE-line-format=LFMT — 🔧 format LTYPE input lines with LFMT

These format options provide fine-grained control over the output of diff, generalizing -D/--ifdef.

LTYPE is 'old', 'new', or 'unchanged'. GTYPE is LTYPE or 'changed'.

GFMT (only) may contain:

%<     lines from FILE1
%>     lines from FILE2
%=     lines common to FILE1 and FILE2
%[-][WIDTH][.[PREC]]{doxX}LETTER  printf-style spec for LETTER
LETTERs are as follows for new group, lower case for old group:
  F      first line number
  L      last line number
  N      number of lines = L-F+1
  E      F-1
  M      L+1
%(A=B?T:E)  if A equals B then T else E

LFMT (only) may contain:

%L     contents of line
%l     contents of line, excluding any trailing newline
%[-][WIDTH][.[PREC]]{doxX}n  printf-style spec for input line number

Both GFMT and LFMT may contain:

%%     %
%c'C'  the single character C
%c'\OOO'  the character with octal code OOO
C      the character C (other characters represent themselves)

• -d, --minimal — 🔧 try hard to find a smaller set of changes
• --horizon-lines=NUM — 🔧 keep NUM lines of the common prefix and suffix
• --speed-large-files — 🚀 assume large files and many scattered small changes
• --color[=WHEN] — 🎨 color output; WHEN is 'never', 'always', or 'auto'; plain --color means --color='auto'
• --palette=PALETTE — 🎨 the colors to use when --color is active; PALETTE is a colon-separated list of terminfo capabilities
• --help — ❓ display this help and exit
• -v, --version — ℹ️ output version information and exit

FILES are 'FILE1 FILE2' or 'DIR1 DIR2' or 'DIR FILE' or 'FILE DIR'. If --from-file or --to-file is given, there are no restrictions on FILE(s). If a FILE is '-', read standard input. Exit status is 0 if inputs are the same, 1 if different, 2 if trouble.

🚪 Exit Codes

• 🔢 0 — inputs are the same
• 🔢 1 — inputs are different
• 🔢 2 — trouble (e.g., file not found, permission denied)

👤 AUTHOR

Written by Paul Eggert, Mike Haertel, David Hayes, Richard Stallman, and Len Tower.

🐛 REPORTING BUGS

Report bugs to: bug-diffutils AT gnu.org

GNU diffutils home page: <https://www.gnu.org/software/diffutils/>

General help using GNU software: <https://www.gnu.org/gethelp/>

©️ COPYRIGHT

Copyright © 2021 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

• wdiff(1)
• cmp(1)
• diff3(1)
• sdiff(1)
• patch(1)

The full documentation for diff is maintained as a Texinfo manual. If the info and diff programs are properly installed at your site, the command

info diff

should give you access to the complete manual.

🗒️ NAME 🚀 Quick Reference 📋 SYNOPSIS 📝 DESCRIPTION 🚪 Exit Codes 👤 AUTHOR 🐛 REPORTING BUGS ©️ COPYRIGHT 🔗 SEE ALSO