最後更新: 2022-05-13
目錄
- 用 cat 寫一段字入檔案(HereDoc)
- echo read from stdin
- Show ALL
- cat 的相反
- Combine File
- Output download to stdout
用 cat 寫一段字入檔案(HereDoc)
"<<"
cat > /etc/apt/sources.list.d/mailscanner.list << EOF deb http://apt.baruwa.org/debian wheezy main EOF
"<<" 與 "<<-" 的分別
"<<-" suppresses leading tabs (not spaces)
cat > ~/.vimrc <<-EOL set bg=dark set modeline EOL
'EOF' & "EOF"
To prevent the variable from expanding
cat > test.txt <<"EOF" $var EOF
echo read from stdin
i.e.
echo Hello | cat Hello
Show ALL
-A, --show-all equivalent to -vET
- -E, --show-ends # display $ at end of each line
- -T, --show-tabs # display TAB characters as ^I
-v, --show-nonprinting
Unix endings (\n) show as $
MAC endings (\r) show as ^M (carriage return character(0xD)) # mac2unix
DOS\Windows endings (\r\n) show as ^M$ (less does not appear to show these)
-e equivalent to -vE
cat 的相反
tac
Combine File
cat 1.txt 2.txt 3.txt > result.txt
result.txt
1 2 2
Output download to stdout
# 如果不使用 "-q" 會有 wget 的 info
wget -q server/ip.php -O - | cat