translating---geekpi Automatically Create/Remove And Mount Swap File In Linux Using Shell Script ============================================================  Few days ago we have covered an article about swap file creation in Linux using three ways which is the common method but it requires manual human effort. Today i have found a small shell script (Two shell script, one for swap file creation and another one for removing swap file) which was written by [Gary Stafford][3] that help us to create/remove & mount swap file automatically in Linux. By default the script create and mount `512MB` swapfile. If you want more swap space and different file name you have to modify the script accordingly. It’s not a big deal to modify the script since it’s very handy and small script, even though i have colored the line where you want to modify the script. **Suggested Read : **[3 Easy Ways To Create Or Extend Swap Space In Linux][4] #### How to check current swap size Lets first check the size of existing swap space partition using **[free][1]** & `swapon` command. ``` $ free -h total used free shared buff/cache available Mem: 2.0G 1.3G 139M 45M 483M 426M Swap: 2.0G 655M 1.4G $ swapon --show NAME TYPE SIZE USED PRIO /dev/sda5 partition 2G 655.2M -1 ``` The above output clearly shows `2GB` is my current swap space. #### Create Swap File Create `create_swap.sh` file and add below script to automate the swap space creation and mounting. ``` $ nano create_swap.sh #!/bin/sh # size of swapfile in megabytes swapsize=1024 # does the swap file already exist? grep -q "swapfile" /etc/fstab # if not then create it if [ $? -ne 0 ]; then echo 'swapfile not found. Adding swapfile.' fallocate -l ${swapsize}M /swapfile chmod 600 /swapfile mkswap /swapfile swapon /swapfile echo '/swapfile none swap defaults 0 0' >> /etc/fstab else echo 'swapfile found. No changes made.' fi echo '--------------------------------------------' echo 'Check whether the swap space created or not?' echo '--------------------------------------------' swapon --show ``` Add execute permission to the file. ``` $ sudo +x create_swap.sh ``` Run the file to create and mount swap file. ``` $ sudo ./create_swap.sh swapfile not found. Adding swapfile. Setting up swapspace version 1, size = 1024 MiB (1073737728 bytes) no label, UUID=d9004261-396a-4321-a45f-9923e3e1328c -------------------------------------------- Check whether the swap space created or not? -------------------------------------------- NAME TYPE SIZE USED PRIO /dev/sda5 partition 2G 954.1M -1 /swapfile file 1024M 0B -2 ``` Yes i can see the new `1024M swapfile`. Reboot the system to use the new swap file. #### Remove Swap File If the swap file is no longer required, then create `remove_swap.sh` file and add below script to remove swap file and its mount point from /etc/fstab. ``` $ nano remove_swap.sh #!/bin/sh # does the swap file exist? grep -q "swapfile" /etc/fstab # if it does then remove it if [ $? -eq 0 ]; then echo 'swapfile found. Removing swapfile.' sed -i '/swapfile/d' /etc/fstab echo "3" > /proc/sys/vm/drop_caches swapoff -a rm -f /swapfile else echo 'No swapfile found. No changes made.' fi echo '--------------------------------------------' echo 'Check whether the swap space removed or not?' echo '--------------------------------------------' swapon --show ``` Add execute permission to the file. ``` $ sudo +x remove_swap.sh ``` Run the file to remve and unmount swap file. ``` $ sudo ./remove_swap.sh swapfile found. Removing swapfile. swapoff: /dev/sda5: swapoff failed: Cannot allocate memory -------------------------------------------- Check whether the swap space removed or not? -------------------------------------------- NAME TYPE SIZE USED PRIO /dev/sda5 partition 2G 951.8M -1 ``` -------------------------------------------------------------------------------- via: http://www.2daygeek.com/shell-script-create-add-extend-swap-space-linux/ 作者：[2DAYGEEK ][a] 译者：[译者ID](https://github.com/译者ID) 校对：[校对者ID](https://github.com/校对者ID) 本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 [a]:http://www.2daygeek.com/author/2daygeek/ [1]:http://www.2daygeek.com/free-command-to-check-memory-usage-statistics-in-linux/ [2]:http://www.2daygeek.com/author/2daygeek/ [3]:https://programmaticponderings.com/2013/12/19/scripting-linux-swap-space/ [4]:http://www.2daygeek.com/add-extend-increase-swap-space-memory-file-partition-linux/