# 1. 在脚本中使用绝对路径
# CMD=$(which command)
# $CMD –version

# 2. 检查命令是否存在
# if ! which command >/dev/null 2>&1; then
echo “Command not found”
exit 1
fi

# 3. 查找命令的所有版本
# which -a python

# 4. 查找命令的文档
# whereis -m command

# 5. 验证命令的完整性
# ls -l $(which command)

# 6. 检查命令的类型
# type command

# 1. 查找命令的路径
# which ls
/usr/bin/ls

# 2. 查找多个命令的路径
# which ls cat grep
/usr/bin/ls
/usr/bin/cat
/usr/bin/grep

# 3. 查找命令的所有路径
# which -a python
/usr/bin/python
/usr/local/bin/python

# 4. 查找系统命令
# which systemctl
/usr/bin/systemctl

# 5. 查找服务管理命令
# which httpd
/usr/sbin/httpd

# 6. 查找用户命令
# which useradd
/usr/sbin/useradd

# 7. 查找网络命令
# which ip
/usr/sbin/ip

# 8. 查找编辑器命令
# which vim
/usr/bin/vim

# 9. 查找Shell内置命令（无结果）
# which cd
/usr/bin/which: no cd in (/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin)

# 10. 查找别名
# alias ll=’ls -l’
# which ll
alias ll=’ls -l’
/usr/bin/ls

# 11. 查找脚本命令
# cat > /usr/local/bin/myscript.sh << 'EOF' #!/bin/bash echo "Hello World" EOF # chmod +x /usr/local/bin/myscript.sh # which myscript.sh /usr/local/bin/myscript.sh # 12. 查找Python命令 # which python3 /usr/bin/python3 # 13. 查找Docker命令 # which docker /usr/bin/docker # 14. 查找Kubernetes命令 # which kubectl /usr/bin/kubectl # 15. 查找Ansible命令 # which ansible /usr/bin/ansible

# 1. 查找命令的所有信息
# whereis ls
ls: /usr/bin/ls /usr/share/man/man1/ls.1.gz /usr/share/man/man1p/ls.1p.gz

# 2. 只查找二进制文件
# whereis -b ls
ls: /usr/bin/ls

# 3. 只查找手册页文件
# whereis -m ls
ls: /usr/share/man/man1/ls.1.gz /usr/share/man/man1p/ls.1p.gz

# 4. 只查找源代码文件
# whereis -s ls
ls:
（大多数系统命令没有源代码）

# 5. 查找多个命令
# whereis ls cat grep
ls: /usr/bin/ls /usr/share/man/man1/ls.1.gz
cat: /usr/bin/cat /usr/share/man/man1/cat.1.gz
grep: /usr/bin/grep /usr/share/man/man1/grep.1.gz

# 6. 查找系统服务命令
# whereis systemctl
systemctl: /usr/bin/systemctl /usr/share/man/man1/systemctl.1.gz

# 7. 查找网络命令
# whereis ip
ip: /usr/sbin/ip /usr/share/man/man8/ip.8.gz

# 8. 查找编辑器命令
# whereis vim
vim: /usr/bin/vim /usr/share/vim /usr/share/man/man1/vim.1.gz

# 9. 查找Python命令
# whereis python
python: /usr/bin/python /usr/lib/python2.7 /usr/lib/python3.9 /usr/share/man/man1/python.1.gz

# 10. 查找Docker命令
# whereis docker
docker: /usr/bin/docker /usr/libexec/docker /usr/share/man/man1/docker.1.gz

# 11. 查找Kubernetes命令
# whereis kubectl
kubectl: /usr/bin/kubectl /usr/share/man/man1/kubectl.1.gz

# 12. 查找Apache命令
# whereis httpd
httpd: /usr/sbin/httpd /usr/share/man/man8/httpd.8.gz

# 13. 查找MySQL命令
# whereis mysql
mysql: /usr/bin/mysql /usr/lib/mysql /usr/share/man/man1/mysql.1.gz

# 14. 查找Nginx命令
# whereis nginx
nginx: /usr/sbin/nginx /usr/share/man/man8/nginx.8.gz

# 15. 查找Git命令
# whereis git
git: /usr/bin/git /usr/share/git /usr/share/man/man1/git.1.gz

# 1. 在脚本中检查命令是否存在
# cat > /tmp/check_command.sh << 'EOF' #!/bin/bash COMMAND=$1 if ! which $COMMAND >/dev/null 2>&1; then
echo “Error: $COMMAND not found”
exit 1
fi

echo “$COMMAND found at: $(which $COMMAND)”
EOF

# chmod +x /tmp/check_command.sh
# /tmp/check_command.sh ls
ls found at: /usr/bin/ls

# 2. 获取命令的绝对路径
# LS_PATH=$(which ls)
# echo $LS_PATH
/usr/bin/ls

# 3. 检查命令的多个版本
# which -a python python3
/usr/bin/python
/usr/bin/python3

# 4. 查找命令并显示详细信息
# ls -l $(which ls)
-rwxr-xr-x. 1 root root 140344 Apr 2 10:00 /usr/bin/ls

# 5. 查找命令并检查权限
# stat $(which ls)
File: /usr/bin/ls
Size: 140344 Blocks: 280 IO Block: 4096 regular file
Device: fd00h/64768d Inode: 1234567 Links: 1
Access: (0755/-rwxr-xr-x) Uid: ( 0/ root) Gid: ( 0/ root)
Context: system_u:object_r:bin_t:s0
Access: 2026-04-02 10:00:00.000000000 +0800
Modify: 2026-04-02 10:00:00.000000000 +0800
Change: 2026-04-02 10:00:00.000000000 +0800
Birth: 2026-04-02 10:00:00.000000000 +0800

# 6. 查找命令的文档
# whereis -m ls
ls: /usr/share/man/man1/ls.1.gz /usr/share/man/man1p/ls.1p.gz

# 查看手册页
# man ls

# 7. 查找命令的源代码
# whereis -s bash
bash:
（大多数系统命令没有源代码）

# 8. 查找命令的配置文件
# find /etc -name “*ls*”
/etc/profile.d/ls.bash

# 9. 检查命令是否被篡改
# rpm -Vf $(which ls)
（无输出表示文件未被修改）

# 10. 查找命令的依赖库
# ldd $(which ls)
linux-vdso.so.1 (0x00007ffc1234)
libselinux.so.1 => /lib64/libselinux.so.1 (0x00007f1234)
libc.so.6 => /lib64/libc.so.6 (0x00007f5678)
libpcre2-8.so.0 => /lib64/libpcre2-8.so.0 (0x00007f9012)
/lib64/ld-linux-x86-64.so.2 (0x00007f3456)

# 11. 查找命令的包名
# rpm -qf $(which ls)
coreutils-8.32-23.el10.x86_64

# 12. 查找命令的所有者
# ls -l $(which ls) | awk ‘{print $3}’
root

# 13. 查找命令的SELinux上下文
# ls -lZ $(which ls)
-rwxr-xr-x. 1 root root system_u:object_r:bin_t:s0 140344 Apr 2 10:00 /usr/bin/ls

# 14. 查找命令的符号链接
# ls -l $(which python)
lrwxrwxrwx. 1 root root 7 Apr 2 10:00 /usr/bin/python -> python3

# 15. 查找命令的版本
# $(which ls) –version
ls (GNU coreutils) 8.32
Copyright (C) 2020 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later .
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by Richard M. Stallman and David MacKenzie.

# 1. 检查命令是否安装
# cat > /usr/local/bin/check_installed.sh << 'EOF' #!/bin/bash COMMAND=$1 if [ -z "$COMMAND" ]; then echo "Usage: $0 ”
exit 1
fi

if which $COMMAND >/dev/null 2>&1; then
echo “$COMMAND is installed at: $(which $COMMAND)”
echo “Version: $($COMMAND –version 2>&1 | head -n 1)”
else
echo “$COMMAND is not installed”
fi
EOF

# chmod +x /usr/local/bin/check_installed.sh
# check_installed.sh docker
docker is installed at: /usr/bin/docker
Version: Docker version 20.10.12, build e91ed57

# 2. 查找命令的多个版本
# which -a python python3 python2
/usr/bin/python
/usr/bin/python3
/usr/bin/python2

# 3. 查找命令的文档位置
# whereis -m systemctl
systemctl: /usr/share/man/man1/systemctl.1.gz

# 查看文档
# man systemctl

# 4. 查找命令的配置文件
# find /etc -name “*systemctl*” 2>/dev/null
/etc/systemd/system.conf

# 5. 查找命令的依赖包
# rpm -qf $(which systemctl)
systemd-249-7.el10.x86_64

# 6. 查找命令的依赖库
# ldd $(which systemctl)
linux-vdso.so.1 (0x00007ffc1234)
libsystemd-shared-249.so => /lib64/libsystemd-shared-249.so (0x00007f1234)
libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f5678)
libc.so.6 => /lib64/libc.so.6 (0x00007f9012)
/lib64/ld-linux-x86-64.so.2 (0x00007f3456)

# 7. 查找命令的SELinux上下文
# ls -lZ $(which systemctl)
-rwxr-xr-x. 1 root root system_u:object_r:systemd_exec_t:s0 123456 Apr 2 10:00 /usr/bin/systemctl

# 8. 查找命令的所有者
# ls -l $(which systemctl) | awk ‘{print $3″:”$4}’
root:root

# 9. 查找命令的权限
# ls -l $(which systemctl) | awk ‘{print $1}’
-rwxr-xr-x.

# 10. 查找命令的安装时间
# rpm -qi $(rpm -qf $(which systemctl)) | grep “Install Date”
Install Date: Thu 02 Apr 2026 10:00:00 AM CST Build Host: server01.fgedu.net

# 1. 检查命令是否存在并执行
# cat > /tmp/run_command.sh << 'EOF' #!/bin/bash COMMAND=$1 if ! which $COMMAND >/dev/null 2>&1; then
echo “Error: $COMMAND not found”
exit 1
fi

$COMMAND “${@:2}”
EOF

# chmod +x /tmp/run_command.sh
# /tmp/run_command.sh ls -l /tmp

# 2. 获取命令的绝对路径
# cat > /tmp/get_path.sh << 'EOF' #!/bin/bash COMMAND=$1 if [ -z "$COMMAND" ]; then echo "Usage: $0 ”
exit 1
fi

PATH=$(which $COMMAND 2>/dev/null)

if [ -z “$PATH” ]; then
echo “Command not found: $COMMAND”
exit 1
fi

echo “Absolute path: $PATH”
EOF

# chmod +x /tmp/get_path.sh
# /tmp/get_path.sh ls
Absolute path: /usr/bin/ls

# 3. 检查多个命令是否安装
# cat > /tmp/check_commands.sh << 'EOF' #!/bin/bash COMMANDS="docker kubectl ansible" for CMD in $COMMANDS; do if which $CMD >/dev/null 2>&1; then
echo “[OK] $CMD: $(which $CMD)”
else
echo “[FAILED] $CMD: not installed”
fi
done
EOF

# chmod +x /tmp/check_commands.sh
# /tmp/check_commands.sh
[OK] docker: /usr/bin/docker
[OK] kubectl: /usr/bin/kubectl
[FAILED] ansible: not installed

# 4. 查找命令并显示详细信息
# cat > /tmp/command_info.sh << 'EOF' #!/bin/bash COMMAND=$1 if [ -z "$COMMAND" ]; then echo "Usage: $0 ”
exit 1
fi

PATH=$(which $COMMAND 2>/dev/null)

if [ -z “$PATH” ]; then
echo “Command not found: $COMMAND”
exit 1
fi

echo “Command: $COMMAND”
echo “Path: $PATH”
echo “Package: $(rpm -qf $PATH)”
echo “Permissions: $(ls -l $PATH | awk ‘{print $1}’)”
echo “Owner: $(ls -l $PATH | awk ‘{print $3″:”$4}’)”
echo “Size: $(ls -lh $PATH | awk ‘{print $5}’)”
EOF

# chmod +x /tmp/command_info.sh
# /tmp/command_info.sh ls
Command: ls
Path: /usr/bin/ls
Package: coreutils-8.32-23.el10.x86_64
Permissions: -rwxr-xr-x.
Owner: root:root
Size: 140K

# 5. 查找命令的文档
# cat > /tmp/find_docs.sh << 'EOF' #!/bin/bash COMMAND=$1 if [ -z "$COMMAND" ]; then echo "Usage: $0 ”
exit 1
fi

DOCS=$(whereis -m $COMMAND | awk ‘{print $2}’)

if [ -z “$DOCS” ]; then
echo “No documentation found for: $COMMAND”
exit 1
fi

echo “Documentation for $COMMAND:”
echo “$DOCS”
EOF

# chmod +x /tmp/find_docs.sh
# /tmp/find_docs.sh ls
Documentation for ls:
/usr/share/man/man1/ls.1.gz /usr/share/man/man1p/ls.1p.gz

# 1. 排查命令找不到的问题
# which command
/usr/bin/which: no command in (/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin)

# 解决方案：安装命令或检查PATH
# echo $PATH
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin

# 2. 排查命令版本问题
# which -a python
/usr/bin/python
/usr/local/bin/python

# 检查版本
# /usr/bin/python –version
Python 2.7.18
# /usr/local/bin/python –version
Python 3.9.7

# 3. 排查命令权限问题
# ls -l $(which command)
-rwx——. 1 root root 123456 Apr 2 10:00 /usr/bin/command

# 解决方案：修改权限
# chmod 755 /usr/bin/command

# 4. 排查命令被篡改问题
# rpm -Vf $(which command)
S.5….T. c /etc/command.conf
（文件被修改）

# 解决方案：重新安装包
# dnf reinstall package_name

# 5. 排查PATH配置问题
# echo $PATH
/usr/local/bin:/usr/bin

# 检查命令是否在其他目录
# find /usr -name “command” 2>/dev/null
/usr/sbin/command

# 解决方案：添加到PATH
# export PATH=$PATH:/usr/sbin

# 6. 排查命令冲突问题
# which -a command
/usr/local/bin/command
/usr/bin/command

# 检查两个命令的区别
# ls -l /usr/local/bin/command /usr/bin/command
-rwxr-xr-x. 1 root root 123456 Apr 2 10:00 /usr/local/bin/command
-rwxr-xr-x. 1 root root 123456 Apr 2 10:00 /usr/bin/command

# 7. 排查命令依赖问题
# ldd $(which command)
linux-vdso.so.1 (0x00007ffc1234)
libmissing.so.1 => not found

# 解决方案：安装缺失的库
# dnf install libmissing

# 8. 排查SELinux问题
# ls -lZ $(which command)
-rwxr-xr-x. 1 root root unconfined_u:object_r:default_t:s0 123456 Apr 2 10:00 /usr/bin/command

# 检查SELinux日志
# ausearch -m AVC -ts recent | grep command

# 解决方案：恢复正确的上下文
# restorecon -v /usr/bin/command