diff

diff命令适用于比较多个文本本件的差异

diff命令格式为：“wc [参数] 文件”

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diff参数

--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

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用例：

diff -c a.log b.log