https://wangdoc.com/bash/grammar.html#echo-%E5%91%BD%E4%BB%A4

    1. [root@dev-yum-server ~]# cat /etc/shells
    2. /bin/sh
    3. /bin/bash
    4. /sbin/nologin
    5. /usr/bin/sh
    6. /usr/bin/bash
    7. /usr/sbin/nologin
    8. /bin/tcsh
    9. /bin/csh
    10. [root@dev-yum-server ~]# echo $SHELL
    11. /bin/bash
    12. [root@dev-yum-server ~]#

    查看bash版本

    1. [root@dev-yum-server ~]# bash --version
    2. GNU bash, version 4.2.46(2)-release (x86_64-redhat-linux-gnu)
    3. Copyright (C) 2011 Free Software Foundation, Inc.
    4. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
    6. This is free software; you are free to change and redistribute it.
    7. There is NO WARRANTY, to the extent permitted by law.
    8. [root@dev-yum-server ~]#
    1. [root@dev-yum-server ~]# echo $BASH_VERSION
    2. 4.2.46(2)-release
    3. [root@dev-yum-server ~]#

    echo

    1. [root@dev-yum-server ~]# echo hello world
    2. hello world
    3. [root@dev-yum-server ~]# echo -n hello world
    4. hello world[root@dev-yum-server ~]# 
    5. [root@dev-yum-server ~]# 
    6. [root@dev-yum-server ~]# echo -n a;echo b
    7. ab
    8. [root@dev-yum-server ~]#

    echo -n

    1. [root@dev-yum-server ~]# echo -n a;echo b
    2. ab
    3. [root@dev-yum-server ~]#

    echo -e

    1. [root@dev-yum-server ~]# echo "Hello\nWorld"
    2. Hello\nWorld
    3. [root@dev-yum-server ~]# 
    4. [root@dev-yum-server ~]# echo -e "Hello\nWorld"
    5. Hello
    6. World
    7. [root@dev-yum-server ~]# echo -e 'Hello\nWorld'
    8. Hello
    9. World
    10. [root@dev-yum-server ~]#

    分号；

    1. [root@dev-yum-server ~]# clear; ls
    2. anaconda-ks.cfg
    3. done
    4. echo
    5. initial-setup-ks.cfg
    6. Install_CSSPC5.0_Linux_64bit_v1.9.47.20200514.tar
    7. Install_CSSPM5.0_Linux_mysql_64bit_v1.8.116.20200512.tar
    8. source
    9. time
    10. vmtools
    11. vmtools-2.5.0.156.tar.bz2
    12. [root@dev-yum-server ~]#
    1. [root@dev-yum-server ~]# w;df -TH
    2.  13:28:02 up 9 days, 12:48,  3 users,  load average: 0.00, 0.01, 0.05
    3. USER     TTY      FROM             LOGIN@   IDLE   JCPU   PCPU WHAT
    4. chroot   pts/1    22.188.80.9      11:07    2.00s  0.17s  0.02s sshd: chroot [priv] 
    5. chroot   pts/2    22.188.80.168    11:44    9:46   0.04s  0.01s ssh root@10.82.100.88
    6. chroot   pts/3    22.188.80.168    12:21   11:14   0.09s  0.08s ssh root@10.82.100.87
    7. Filesystem              Type      Size  Used Avail Use% Mounted on
    8. /dev/mapper/rootvg-root ext4       11G  5.0G  4.9G  51% /
    9. devtmpfs                devtmpfs  4.1G     0  4.1G   0% /dev
    10. tmpfs                   tmpfs     4.2G     0  4.2G   0% /dev/shm
    11. tmpfs                   tmpfs     4.2G   27M  4.1G   1% /run
    12. tmpfs                   tmpfs     4.2G     0  4.2G   0% /sys/fs/cgroup
    13. /dev/mapper/rootvg-usr  ext4       11G  3.6G  6.3G  37% /usr
    14. /dev/vda1               xfs       534M  213M  321M  40% /boot
    15. /dev/vda2               vfat      1.1G   13k  1.1G   1% /boot/efi
    16. /dev/mapper/rootvg-var  ext4       11G  780M  9.2G   8% /var
    17. /dev/mapper/rootvg-home ext4       11G   43M  9.9G   1% /home
    18. /dev/mapper/rootvg-tmp  ext4       11G  280M  9.7G   3% /tmp
    19. /dev/mapper/rootvg-opt  ext4       11G  125M  9.8G   2% /opt
    20. /dev/mapper/rootvg-app  ext4       11G   38M  9.9G   1% /app
    21. /dev/loop0              iso9660   4.1G  4.1G     0 100% /yum/rehl7.4
    22. tmpfs                   tmpfs     821M   13k  821M   1% /run/user/42
    23. tmpfs                   tmpfs     821M     0  821M   0% /run/user/1000
    24. [root@dev-yum-server ~]#

    && 成功后才执行后面
    || 成功后就不执行后面的

    1. [root@dev-yum-server ~]# ls -l && w
    2. total 673888
    3. -rw-------. 1 root root      2401 May  7 16:57 anaconda-ks.cfg
    4. -rw-r--r--  1 root root         0 Jun 26 11:20 done
    5. -rw-r--r--  1 root root         0 Jun 26 11:20 echo
    6. -rw-r--r--. 1 root root      2449 May  7 16:59 initial-setup-ks.cfg
    7. -rw-r--r--  1 root root 151848960 May 18 10:22 Install_CSSPC5.0_Linux_64bit_v1.9.47.20200514.tar
    8. -rw-r--r--  1 root root 519802880 May 18 10:21 Install_CSSPM5.0_Linux_mysql_64bit_v1.8.116.20200512.tar
    9. drwxr-xr-x  3 root root      4096 May 28 13:19 source
    10. -rw-r--r--  1 root root         0 Jun 26 11:20 time
    11. drwxr-xr-x. 6 root root      4096 Aug  1  2019 vmtools
    12. -r--r--r--. 1 root root  18380837 May  7 17:09 vmtools-2.5.0.156.tar.bz2
    13.  13:31:03 up 9 days, 12:51,  3 users,  load average: 0.00, 0.01, 0.05
    14. USER     TTY      FROM             LOGIN@   IDLE   JCPU   PCPU WHAT
    15. chroot   pts/1    22.188.80.9      11:07    7.00s  0.18s  0.02s sshd: chroot [priv] 
    16. chroot   pts/2    22.188.80.168    11:44   23.00s  0.04s  0.01s ssh root@10.82.100.88
    17. chroot   pts/3    22.188.80.168    12:21   14:15   0.09s  0.08s ssh root@10.82.100.87
    18. [root@dev-yum-server ~]# ls -l || w
    19. total 673888
    20. -rw-------. 1 root root      2401 May  7 16:57 anaconda-ks.cfg
    21. -rw-r--r--  1 root root         0 Jun 26 11:20 done
    22. -rw-r--r--  1 root root         0 Jun 26 11:20 echo
    23. -rw-r--r--. 1 root root      2449 May  7 16:59 initial-setup-ks.cfg
    24. -rw-r--r--  1 root root 151848960 May 18 10:22 Install_CSSPC5.0_Linux_64bit_v1.9.47.20200514.tar
    25. -rw-r--r--  1 root root 519802880 May 18 10:21 Install_CSSPM5.0_Linux_mysql_64bit_v1.8.116.20200512.tar
    26. drwxr-xr-x  3 root root      4096 May 28 13:19 source
    27. -rw-r--r--  1 root root         0 Jun 26 11:20 time
    28. drwxr-xr-x. 6 root root      4096 Aug  1  2019 vmtools
    29. -r--r--r--. 1 root root  18380837 May  7 17:09 vmtools-2.5.0.156.tar.bz2
    30. [root@dev-yum-server ~]#

    type 判断命令来源

    1. [root@dev-yum-server ~]# type echo
    2. echo is a shell builtin
    3. [root@dev-yum-server ~]# type w
    4. w is hashed (/bin/w)
    5. [root@dev-yum-server ~]#

    快捷方式

    1. Ctrl + U：从光标位置删除到行首
    2. Ctrl + K：从光标位置删除到行尾