Bash
- 配置
- .inputrc
- .bashrc - 交互 shell
- .profile, .bash_profile - 登陆 shell
- 参考
# empty shell
env -i bash
# empty env
env -i HOME="$HOME" bash -c 'env'
# login shell
time env -i HOME="$HOME" LOG4BASH_LOG_LEVE=DEBUG /usr/local/bin/bash -l -c 'env'
| flag | for |
|---|---|
| -c COMMAND | command string |
| -i | interactive |
| -l | login shell |
| -r | restricted |
| -s | stdin |
# 传递 flag 给 stdin 脚本
curl http://sh | bash -s -- -flag
语法
[= test[[- shell 内置语法 - 速度更快一点点- 支持
&&,||语法
- 支持
{}- 展开${var}${var:=default}${var/find/replace}${var%remove}{000..2}- 序列展开{000..2..2}- 带 step 参数echo x{,A,B,C}- 组合展开{ echo 1; echo 2; }- 命令序列
(())- 算术操作()- subshell, array
# for 循环
# ===========
# bash 语法
for ((i = 0; i < 3; i++)); do echo $i; done
# bash 展开序列
for i in {0..2}; do echo $i; done
# 使用 seq 生成序列 - ash 支持
for i in $(seq 0 2); do echo $i; done
for i in $(seq 0 $((3 - 1))); do echo $i; done
set
# 推荐
set -Eeuo pipefail
shopt
- Bash 扩展选项
shopt [-pqsu] [-o] [optname …]
shopt -s extglob # 开启
shopt -u extglob # 关闭
shopt -q extglob # 使用 exit code 表示是否开启
shopt extglob # 当前状态
shopt # 全部状态
shopt -o nolog # 限定内置 set 支持选项而非扩展选项
# 所有 on 的选项
shopt | grep "on$" | grep -o '^\S\+'
# 推荐
shopt -s autocd cdspell extglob globstar
# 默认开启选项
shopt -s checkwinsize cmdhist expand_aliases extquote force_fignore hostcomplete interactive_comments progcomp promptvars sourcepath
- globstar -
**会匹配当前而不只是子目录# 会匹配 Makefile
ls **/Makefile - extglob - 扩展 glob 语法
[?*+@!](pattern-list)!排除@匹配 1 个
- Pattern Matching
# 复制 scripts 下的 Makefile 到所有其他 Makefile
ls !(scripts)/**/Makefile | xargs -n 1 cp scripts/stub/Makefile - nocaseglob - glob 大小写不敏感
- histappend - 追加到历史文件而不是重写
- cdspell - 使用 cd 时自动校正书写
cd ignorad # 会 cd 到存在的 ignored 目录 - a -> e - autocd - 输入目录自动切换到目录
- failglob - glob 匹配不到文件时出错而非 直接输出相同字符
环境变量
| env | default | description |
|---|---|---|
| EPOCHSECONDS | ||
| EPOCHREALTIME | ||
| BASH_ARGV0 |
echo $EPOCHSECONDS
.inputrc
C-x C-r is bound to re-read-init-file.
https://www.gnu.org/software/bash/manual/html_node/Readline-Init-File.html
https://www.gnu.org/software/bash/manual/bashref.html#Miscellaneous-Commands
# Make Tab autocomplete regardless of filename case
set completion-ignore-case on
# List all matches in case multiple possible completions are possible
set show-all-if-ambiguous on
# Immediately add a trailing slash when autocompleting symlinks to directories
set mark-symlinked-directories on
# Use the text that has already been typed as the prefix for searching through
# commands (i.e. more intelligent Up/Down behavior)
"\eOA": history-search-backward
"\e[A": history-search-backward
"\eOB": history-search-forward
"\e[B": history-search-forward
FAQ
Prefix/Suffix
# 去除前缀和后缀
x="/foo/fizzbuzz.bar"
y=${x%.bar}
echo ${y##*/}
#> fizzbuzz
# 去除后缀
x="/foo/fizzbuzz.bar.quux"
y=${x%.*}
echo $y
#> /foo/fizzbuzz.bar
y=${x%%.*}
echo $y
#> /foo/fizzbuzz
# 去除前缀
x=/foo/bar/bim/baz/file.gif
y=${path##*/}
echo $y
#> file.gif
替换
a=abc/da
# zbc/da
echo ${a/a/z}
# // 是所有
# zbc/dz
echo ${a//a/z}
# 转意
# abczda
echo ${a//\//z}
Parallels
# do it once
seq 1 | parallel -n0 "curl -H 'Content-Type: application/json' http://httpbin.org/post -X POST -d '{\"url\":\"http://google.com/\"}'"
# do it twice
seq 2 | parallel -n0 "curl -H 'Content-Type: application/json' http://httpbin.org/post -X POST -d '{\"url\":\"http://google.com/\"}'"
# do it 4 times, but at 2 a time
seq 4 | parallel -n0 -j2 "curl -H 'Content-Type: application/json' http://httpbin.org/post -X POST -d '{\"url\":\"http://google.com/\"}'"
# you can also put all your commands into a file
echo "ls\nls" > somefile
cat somefile | parallel
# finally, just straight command line parameters
parallel echo ::: a b c
# by default, it runs as many jobs in parallel as there are cores in your computer
# if you try and set more jobs than there are cores, they will be concurrent, but
# they will only ever be parallel up to your core count
# for httpie use the --ignore-stdin flag, or else it gets mixed up
seq 1 | parallel -n0 "http --ignore-stdin POST http://httpbin.org/post url=http://google.com/"
Base N
# Encode base62
BASE62=($(echo {0..9} {a..z} {A..Z}))
for i in $(bc <<< "obase=62; 9207903953"); do
echo -n ${BASE62[$(( 10#$i ))]}
done && echo
# Decode base62
base62_decode() { echo $((62#$1)) }
SSH
# download: remote -> local
# local_file 可以为目录用 -r 递归
scp user@remote_host:remote_file local_file
# upload: local -> remote
scp local_file user@remote_host:remote_file
# To Forward sshtalk.in:8080 -> Cort.local:4567, you can do
local="Cort.local:4567" # or "localhost:4567"
remot="*:8080" # "*" for all interfaces (default is loopback)
ssh -R ${remote}:${local} sshtalk.in
# To forward localhost:1234 -> private-host:443, through public-host you can do
local="localhost:1234" # or just "1234" default is localhost
remot="private-host:443" # "*" for all interfaces (default is loopback)
ssh -L ${local}:${remote} public-host
# 须在在Server端允许转发
# 在 /etc/ssh/sshd_config 中添加
# GatewayPorts yes
# 然后重启
sudo service sshd restart
# scp to 多台
for dest in $(< destfile.txt); do
scp ourfile.txt ${dest}:remote/path/
done
# 在不用 scp 的情况下 拷贝到多台
cat file.txt | tee \
>(ssh [email protected] "cat > file.txt") \
>(ssh [email protected] "cat > file.txt")
tar cz file1 file2 file3 | tee \
>(ssh [email protected] "tar xz") \
>(...)
xargs
case
case $space in
[1-6]*)
Message="All is quiet."
;;
[7-8]*)
Message="Start thinking about cleaning out some stuff. There's a partition that is $space % full."
;;
9[1-8])
Message="Better hurry with that new disk... One partition is $space % full."
;;
99)
Message="I'm drowning here! There's a partition at $space %!"
;;
*)
Message="I seem to be running with an nonexistent amount of disk space..."
;;
esac
使用变量名字访问变量
a=PATH
echo ${!a}
dotenv
env $(cat .env | xargs) sh -c 'echo $MY_ENV'
heredoc
cat << EOF
PWD=$PWD
EOF
# 转义
cat << "EOF"
PWD=$PWD
EOF
# 移除缩进 - 需要 tab
cat <<- EOF
PWD=$PWD
EOF
sub shell
(echo 1)
# 会输出 1 2 3 4
bash << SH &
echo 1
echo 2 && (echo 3; exit 1;)
echo 4
SH
tcp redir
echo <> /dev/tcp/wener.me/80
# 0 - 连通
echo $?
echo <> /dev/tcp/localhost/80
# 1
echo $?
git branch
curl -Lo ~/.git-prompt.sh https://github.com/git/git/raw/master/contrib/completion/git-prompt.sh
source ~/.git-prompt.sh
__git_ps1 '%s'
export PS1='\[\e[32m\]\u@\h \[\e[01;33m\]\w $(__git_ps1 " (%s)") \[\e[34m\][\t] \[\e[0m\]\n$ '