linux备忘小知识
2020-12-30 本文已影响0人
千转军师
作者：along
时间：2020年12月30日10:45:12
1、增加自己的命令
描述：假如我想增加一个文件内容重定向到指定文件，例如 out <file>
- 1、脚本
out文件
#!/bin/sh
# redirect text stream
#usage: <this cmd> <file1>
OUT_FILE="/mnt/hgfs/share/tmp.c"
cat $1 > ${OUT_FILE}
echo "redirect $1 succussed"
- 2、永久添加路径
打开/etc/profile这个配置文件
适当位置’添加 export PATH=${PATH}:<自定义脚本的路径>
使新的环境变量生效
source /etc/profile - 3、遇到问题
在/etc/profile配置文件文件中添加
export PATH=<自定义脚本的路径>
丢失了原来的PATH，结果vim都用不了。
解决方法：
（1）进入/bincd /bin
（2）打开/etc/profilevim /etc/profile
（3）把export PATH=<自定义脚本的路径>改掉，换成export PATH=${PATH}:<自定义脚本的路径>
（4）重启reboot
注：重启会载入profile文件时候，估计把默认路径添加上去了，所以之前对PATH的错误设置会得到修复。
2、gcc命令
[root@liu lib]# gcc --help
Usage: gcc [options] file...
Options:
| 操作 | en | 描述 |
|---|---|---|
| -pass-exit-codes | Exit with highest error code from a phase | |
| --help | Display this information | |
| --target-help | Display target specific command line options | |
| --help={common|optimizers|params|target|warnings|[^]{joined|separate|undocumented}}[,...] | Display specific types of command line options (Use '-v --help' to display command line options of sub-processes) | |
| --version | Display compiler version information | |
| -dumpspecs | Display all of the built in spec strings | |
| -dumpversion | Display the version of the compiler | |
| -dumpmachine | Display the compiler's target processor | |
| -print-search-dirs | Display the directories in the compiler's search path | |
| -print-libgcc-file-name | Display the name of the compiler's companion library | |
| -print-file-name=<lib> | Display the full path to library <lib> | |
| -print-prog-name=<prog> | Display the full path to compiler component <prog> | |
| -print-multiarch | Display the target's normalized GNU triplet, used as a component in the library path | |
| -print-multi-directory | Display the root directory for versions of libgcc | |
| -print-multi-lib | Display the mapping between command line options and multiple library search directories | |
| -print-multi-os-directory | Display the relative path to OS libraries | |
| -print-sysroot | Display the target libraries directory | |
| -print-sysroot-headers-suffix Display | the sysroot suffix used to find headers | |
| -Wa,<options> | Pass comma-separated <options> on to the assembler | |
| -Wp,<options> | Pass comma-separated <options> on to the preprocessor | |
| -Wl,<options> | Pass comma-separated <options> on to the linker | |
| -Xassembler <arg> | Pass <arg> on to the assembler | |
| -Xpreprocessor <arg> | Pass <arg> on to the preprocessor | |
| -Xlinker <arg> | Pass <arg> on to the linker | |
| -save-temps | Do not delete intermediate files | |
| -save-temps=<arg> | Do not delete intermediate files | |
| -no-canonical-prefixes | Do not canonicalize paths when building relative prefixes to other gcc components | |
| -pipe | Use pipes rather than intermediate files | |
| -time | Time the execution of each subprocess | |
| -specs=<file> | Override built-in specs with the contents of <file> | |
| -std=<standard> | Assume that the input sources are for <standard> | |
| --sysroot=<directory> | Use <directory> as the root directory for headers and libraries | |
| -B <directory> | Add <directory> to the compiler's search paths | |
| -v | Display the programs invoked by the compiler | |
| -### | Like -v but options quoted and commands not executed | |
| -E | Preprocess only; do not compile, assemble or link | |
| -S | Compile only; do not assemble or link | |
| -c | Compile and assemble, but do not link | 预处理且编译为汇编文件，但是不链接 |
| -o <file> | Place the output into <file> | 决定输出文件存放地方 |
| -pie | Create a position independent executable | |
| -shared | Create a shared library | |
| -x <language> | Specify the language of the following input files Permissible languages include: c c++ assembler none 'none' means revert to the default behavior of guessing the language based on the file's extension |
Options starting with -g, -f, -m, -O, -W, or --param are automatically
passed on to the various sub-processes invoked by gcc. In order to pass
other options on to these processes the -W<letter> options must be used.
